Fix for loading state of Fast Refresh from user defaults (facebook#29880

)

Summary:
Disabling Fast Refresh won't be persisted when restarting the app.

I believe this regressed with facebook@824e171. In this commit `HMRClient.setup` will always be called with `enabled` being set true. This PR loads the _enabled_ state from the user defaults (as it was done before).

## Changelog

[iOS] [Fixed] - Enable Fast Refresh gets persisted across app launches

Pull Request resolved: facebook#29880

Test Plan:
Without this change Fast Refresh is enabled on every app restart.

Tested with this change:
- Disabling Fast Refresh
- Restarting App -> Fast Refresh still disabled
- Enabled Fast Refresh again
- Restarting App -> Fast Refresh still enabled again

Reviewed By: sammy-SC

Differential Revision: D23686435

Pulled By: PeteTheHeat

fbshipit-source-id: 42c31b22060d3dc4b1d4cb8f41792b303fc7fce8

React/CoreModules/RCTDevSettings.mm

@@ -405,17 +405,18 @@ - (void)addHandler:(id<RCTPackagerClientMethod>)handler forPackagerMethod:(NSStr
 
 - (void)setupHotModuleReloadClientIfApplicableForURL:(NSURL *)bundleURL
 {
-  if (bundleURL && !bundleURL.fileURL) { // isHotLoadingAvailable check
+  if (bundleURL && !bundleURL.fileURL) {
     NSString *const path = [bundleURL.path substringFromIndex:1]; // Strip initial slash.
     NSString *const host = bundleURL.host;
     NSNumber *const port = bundleURL.port;
+    BOOL isHotLoadingEnabled = self.isHotLoadingEnabled;
     if (self.bridge) {
       [self.bridge enqueueJSCall:@"HMRClient"
                           method:@"setup"
-                            args:@[ @"ios", path, host, RCTNullIfNil(port), @(YES) ]
+                            args:@[ @"ios", path, host, RCTNullIfNil(port), @(isHotLoadingEnabled) ]
                       completion:NULL];
     } else {
-      self.invokeJS(@"HMRClient", @"setup", @[ @"ios", path, host, RCTNullIfNil(port), @(YES) ]);
+      self.invokeJS(@"HMRClient", @"setup", @[ @"ios", path, host, RCTNullIfNil(port), @(isHotLoadingEnabled) ]);
     }
   }
 }