ExceptionsManager: Fix soft error reporting (#47465)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47465

When you do @(NO), in objc, it creates an NSNumber.

So this if condition actually evaluates to true:

```
if (@(NO))
```

This means that all soft errors will get logged as fatals on ios.

Changelog: [Internal]

Created from CodeHub with https://fburl.com/edit-in-codehub

Reviewed By: realsoelynn

Differential Revision: D65551648

fbshipit-source-id: 99b5bcb5fa1b0b5dc8055a3c86fc983863a25526

packages/react-native/React/CoreModules/RCTExceptionsManager.mm

@@ -155,7 +155,7 @@ RCT_EXPORT_METHOD(reportException : (JS::NativeExceptionsManager::ExceptionData
   NSArray<NSDictionary<NSString *, id> *> *stack = errorData[@"stack"];
   double exceptionId = [errorData[@"id"] doubleValue];
 
-  if (errorData[@"isFatal"]) {
+  if ([errorData[@"isFatal"] boolValue]) {
     [self reportFatal:message stack:stack exceptionId:exceptionId extraDataAsJSON:extraDataAsJSON];
   } else {
     [self reportSoft:message stack:stack exceptionId:exceptionId extraDataAsJSON:extraDataAsJSON];