Change default suppress-errors boolean to true, not false

If this value is not set explicitly, a false value means that an error
from a termshark-initiated tshark process will result in an error dialog
in the termshark UI. I am seeing this more and more as I test with
various pcaps - it always comes from tshark serializing characters into
XML text that are invalid, according to the XML spec (val <= 31 and val
not in {tab, CR, LF}). Here is a merge request against Wireshark to try
to solve this problem at the source:
https://gitlab.com/wireshark/wireshark/-/merge_requests/7398

To see the problem, try this:

$ wget https://storage.googleapis.com/gcla3/xmlbug.pcapng
$ tshark -r xmlbug.pcapng -T pdml | xmllint --noout - || echo bad xml

Even if this Wireshark request is merged, it will presumably be a long
time before all termshark-used tsharks are updated. So I think the more
user-friendly option is to suppress these errors to avoid popups about
which the user can do very little anyway.

Here's a hack you can use if you want to see errors, in general, but are
not interested in this specific XML error:

#133 (comment)

Workaround:

- create the following file called e.g. /usr/local/bin/tshark-hack

if [[ " $* " =~ " pdml " ]]; then
    exec tshark "$@" | tr -cd '\11\12\15\40-\176'
else
    exec tshark "$@"
fi

- run:

$ sudo chmod +x /usr/local/bin/tshark-hack

- edit ~/.config/termshark/termshark.toml

[main]
  tshark = "/usr/local/bin/tshark-hack"

ui/prochandlers.go

@@ -122,7 +122,7 @@ func (t updatePacketViews) OnError(code pcap.HandlerCode, app gowid.IApp, err er
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		RequestQuit()
 	} else {
-		if !profiles.ConfBool("main.suppress-tshark-errors", false) {
+		if !profiles.ConfBool("main.suppress-tshark-errors", true) {
 			var errstr string
 			if kverr, ok := err.(gowid.KeyValueError); ok {
 				errstr = fmt.Sprintf("%v\n\n", kverr.Cause())
@@ -160,7 +160,7 @@ func (t SimpleErrors) OnError(code pcap.HandlerCode, app gowid.IApp, err error)
 	log.Error(err)
 	// Hack to avoid picking up errors at other parts of the load
 	// cycle. There should be specific handlers for specific errors.
-	if !profiles.ConfBool("main.suppress-tshark-errors", false) {
+	if !profiles.ConfBool("main.suppress-tshark-errors", true) {
 		app.Run(gowid.RunFunction(func(app gowid.IApp) {
 			OpenError(fmt.Sprintf("%v", err), app)
 		}))
@@ -379,7 +379,7 @@ func (s SetStructWidgets) OnError(code pcap.HandlerCode, app gowid.IApp, err err
 	// Hack to avoid picking up errors at other parts of the load
 	// cycle. There should be specific handlers for specific errors.
 	if s.Ld.PdmlLoader.IsLoading() {
-		if !profiles.ConfBool("main.suppress-tshark-errors", false) {
+		if !profiles.ConfBool("main.suppress-tshark-errors", true) {
 			app.Run(gowid.RunFunction(func(app gowid.IApp) {
 				OpenLongError(fmt.Sprintf("%v", err), app)
 			}))

ui/streamui.go

@@ -340,7 +340,7 @@ func (t *streamParseHandler) OnError(code pcap.HandlerCode, app gowid.IApp, err
 	if !Running {
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		RequestQuit()
-	} else if !profiles.ConfBool("main.suppress-tshark-errors", false) {
+	} else if !profiles.ConfBool("main.suppress-tshark-errors", true) {
 		var errstr string
 		if kverr, ok := err.(gowid.KeyValueError); ok {
 			errstr = fmt.Sprintf("%v\n\n", kverr.Cause())