Drop RCT_EXPORT_METHOD from RCTExceptionsManager TurboModule (#57684)

Summary:
Pull Request resolved: #57684

Changelog: [Internal]

`RCTExceptionsManager` is a TurboModule: it conforms to `NativeExceptionsManagerSpec` and implements `getTurboModule:` returning the codegen'd `...SpecJSI`. For TurboModules, the JS->ObjC dispatch is driven by codegen (the generated spec supplies the `selector` and argument kinds, invoked at runtime via `NSMethodSignature` / `NSInvocation`), not by the `RCT_EXPORT_METHOD` macro's `__rct_export__` metadata.

The exported methods here are async-void with concrete parameter types (no generic `id` requiring `RCTConvert` coercion), so the macro is not functionally required. Convert them to plain ObjC method declarations; conformance to the codegen'd `NativeExceptionsManagerSpec` protocol keeps compiler-enforced signature parity.

Signature-only refactor with no change to the JS-facing API. Sync methods, methods with `id` params, and `constantsToExport` are intentionally left untouched.

Reviewed By: cortinico

Differential Revision: D113579875

fbshipit-source-id: 41aaed7f15443da5aadc0c18735732d4811dbe9b

Author: christophpurrer

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

@@ -87,24 +87,22 @@ - (void)reportFatal:(NSString *)message
 }
 
 // TODO(T205456329): This method is deprecated in favour of reportException. Delete in v0.77
-RCT_EXPORT_METHOD(
-    reportSoftException : (NSString *)message stack : (NSArray<NSDictionary *> *)stack exceptionId : (double)
-        exceptionId)
+- (void)reportSoftException:(NSString *)message stack:(NSArray<NSDictionary *> *)stack exceptionId:(double)exceptionId
 {
   [self reportSoft:message stack:stack exceptionId:exceptionId extraDataAsJSON:nil];
 }
 
 // TODO(T205456329): This method is deprecated in favour of reportException. Delete in v0.77
-RCT_EXPORT_METHOD(
-    reportFatalException : (NSString *)message stack : (NSArray<NSDictionary *> *)stack exceptionId : (double)
-        exceptionId)
+- (void)reportFatalException:(NSString *)message stack:(NSArray<NSDictionary *> *)stack exceptionId:(double)exceptionId
 {
   [self reportFatal:message stack:stack exceptionId:exceptionId extraDataAsJSON:nil];
 }
 
-RCT_EXPORT_METHOD(dismissRedbox) {}
+- (void)dismissRedbox
+{
+}
 
-RCT_EXPORT_METHOD(reportException : (JS::NativeExceptionsManager::ExceptionData &)data)
+- (void)reportException:(JS::NativeExceptionsManager::ExceptionData &)data
 {
   NSMutableDictionary<NSString *, id> *mutableErrorData = [NSMutableDictionary new];
   mutableErrorData[@"message"] = data.message();