connect [nfc]: Work around Flow bug by making types more explicit.

Flow was determining that these components produced with `connect`
had type `ComponentType<empty>`, which you can see by hovering over
them in the editor wherever they're imported and used.  That means
that absolutely any set of props was acceptable to pass to them,
which is unsound.  This affected `connect` calls with a two-argument
`mapStateToProps`.

This is certainly a bug in Flow, because it's possible to work
around it in a way that doesn't give Flow any information it didn't
already have:

    const X = connect(/* ... */); // the exact same expression as before

    // $FlowFixMe
    const y = () => <X />;

    export default X;

This causes, for example, `AccountDetails` to have the beautifully
specific type `ComponentType<{| +user: User |}>`, instead of the
unsound `ComponentType<empty>`.

Fortunately, it's also possible to work around in this other way,
which adds almost no net boilerplate.  Do that.

Change prepared mechanically, like so:

  $ perl -i -0pe '
      s/connect(.*?): SelectorProps/connect<SelectorProps, _, _>$1/g
    ' src/**/*.js

Fixes: #3768
Debugged-by: Chris Bobbe <cbobbe@zulipchat.com>
Debugged-by: Ray Kraesig <rkraesig@zulipchat.com>

src/account-info/AccountDetails.js

@@ -71,7 +71,7 @@ class AccountDetails extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   realm: getCurrentRealm(state),
   userStatusText: getUserStatusTextForUser(state, props.user.user_id),
 }))(AccountDetails);

src/chat/Chat.js

@@ -52,6 +52,6 @@ class Chat extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   canSend: canSendToNarrow(props.narrow) && !getShowMessagePlaceholders(props.narrow)(state),
 }))(Chat);

src/chat/UnreadNotice.js

@@ -66,6 +66,6 @@ class UnreadNotice extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   unreadCount: getUnreadCountForNarrow(state, props.narrow),
 }))(UnreadNotice);

src/compose/ComposeBox.js

@@ -412,7 +412,7 @@ class ComposeBox extends PureComponent<Props, State> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   auth: getAuth(state),
   ownEmail: getOwnEmail(state),
   usersByEmail: getActiveUsersByEmail(state),

src/emoji/Emoji.js

@@ -39,6 +39,6 @@ class Emoji extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   imageEmoji: getAllImageEmojiByName(state)[props.name],
 }))(Emoji);

src/message/NoMessages.js

@@ -78,7 +78,7 @@ class NoMessages extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   showMessagePlaceholders: getShowMessagePlaceholders(props.narrow)(state),
   noMessages: getIfNoMessages(props.narrow)(state),
 }))(NoMessages);

src/nav/ChatNavBar.js

@@ -49,6 +49,6 @@ class ChatNavBar extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   backgroundColor: getTitleBackgroundColor(props.narrow)(state),
 }))(ChatNavBar);

src/reactions/MessageReactionList.js

@@ -113,7 +113,7 @@ class MessageReactionList extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   message: state.messages[props.navigation.state.params.messageId],
   ownUserId: getOwnUser(state).user_id,
   allUsersById: getAllUsersById(state),

src/start/RealmScreen.js

@@ -123,6 +123,6 @@ class RealmScreen extends PureComponent<Props, State> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   initialRealm: props.navigation.state.params?.realm ?? '',
 }))(RealmScreen);

src/title-buttons/InfoNavButtonGroup.js

@@ -33,6 +33,6 @@ class InfoNavButtonGroup extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   recipients: getRecipientsInGroupNarrow(state, props.narrow),
 }))(InfoNavButtonGroup);

src/title/TitleStream.js

@@ -70,6 +70,6 @@ class TitleStream extends PureComponent<Props> {
   }
 }
 
-export default connect((state, props): SelectorProps => ({
+export default connect<SelectorProps, _, _>((state, props) => ({
   stream: getStreamInNarrow(props.narrow)(state),
 }))(TitleStream);

src/webview/MessageList.js

@@ -320,7 +320,7 @@ type OuterProps = {|
   typingUsers?: User[],
 |};
 
-export default connect((state, props: OuterProps): SelectorProps => {
+export default connect<SelectorProps, _, _>((state, props: OuterProps) => {
   // TODO Ideally this ought to be a caching selector that doesn't change
   // when the inputs don't.  Doesn't matter in a practical way here, because
   // we have a `shouldComponentUpdate` that doesn't look at this prop... but