fix: update iOS TurboModule template (#889)

### Summary

Updates iOS `.mm` TurboModule template file to match
https://reactnative.dev/docs/turbo-native-modules-introduction#4-write-your-native-platform-code

### Test plan

Module generates correctly, app consuming it builds as expected

Author: krozniata

packages/create-react-native-library/templates/objc-library/ios/{%- project.name %}.mm

@@ -2,8 +2,6 @@
 
 @implementation <%- project.name -%>
 
-RCT_EXPORT_MODULE()
-
 - (NSNumber *)multiply:(double)a b:(double)b {
     NSNumber *result = @(a * b);
 
@@ -16,4 +14,9 @@ - (NSNumber *)multiply:(double)a b:(double)b {
     return std::make_shared<facebook::react::Native<%- project.name -%>SpecJSI>(params);
 }
 
++ (NSString *)moduleName
+{
+  return @"<%- project.name -%>";
+}
+
 @end