Silence warning "Class RCTCxxModule was not exported"

[chrisballinger]

On a relatively stock / default setup of RN on iOS you'll see the warning "Class RCTCxxModule was not exported. Did you forget to use RCT_EXPORT_MODULE()?" pop up on every launch. This change resolves that issue.

Fixes #14806

Test Plan

Try a fresh project by following the RN iOS tutorial, and observe that there are no more warnings after making this change.

Release Notes

[IOS] [MINOR] [CxxBridge] - Fix "Class RCTCxxModule was not exported"

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[douglowder]

@shergin I'm hitting this also... is the fix in this PR ok, or should this class name be filtered out in RCTBridge.m?

e.g.

         if (isModuleSuperClass) {
           break;
         }
+        
+        if (strncmp(class_getName(superclass), "RCTCxxModule", strlen("RCTCxxModule")) == 0) {
+          break;
+        }
 
         RCTLogWarn(@"Class %@ was not exported. Did you forget to use RCT_EXPORT_MODULE()?", cls);
         break;

[javache]

Yes, the module should not be exported. Instead the module should be ignored in RCTVerifyAllModulesExported.

[douglowder]

@chrisballinger This module should not be exported. See @javache 's comment, and the code snippet I provided that fixes the issue in a safer way.

[douglowder]

@chrisballinger thanks for submitting this PR -- I've implemented the alternative fix requested by @javache in a separate PR and will get that merged as soon as CI passes.

[chrisballinger]

@dlowder-salesforce @javache Awesome thanks!

[keshavkaul]

@chrisballinger @dlowder-salesforce @javache
FYI, I'm seeing this issue in react version 0.56.0-rc.4 released 16 hrs ago.
Is this fix present in the latest RC?