fix(grpc): Update GrpcLoaderHelper to use rootId for root json naming

[iamchanii]

Description

This pull request changes the logic of the getDescriptorSets method of the GrpcLoaderHelper class.

Previously, if the Protobuf Root did not have a name, it utilized an index to determine the name. This could cause the GrpcTransportHelper to select the wrong grpcRootJson directory when there was more than one gRPC Subgraph with an unnamed Protobuf Root.

So I put a variable called rootId in the module with the GrpcLoaderHelper class, and changed it to use that variable to determine the name instead of the index.

Related #7962

Type of change

• Bug fix (non-breaking change which fixes an issue)

Screenshots/Sandbox (if appropriate/relevant):

N/A

How Has This Been Tested?

I have confirmed that the issue is fixed with a patch in the issue reproduction branch that reflects the changes in this pull request.

• Reproduce branch(commit): 8f9b8ee
• Patch commit: 7494ec3

As mentioned in #7962 (comment), To fix the issue, it needs to be changed to allow passing directives when calling mergeDirectives.

Checklist:

• I have followed the
  CONTRIBUTING doc and the
  style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works, and I have added a
  changeset using yarn changeset that bumps the version
• New and existing unit tests and linter rules pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Further comments

N/A

[ardatan]

Thanks for the PR 🙏
We appreciate your feedback and effort.
The issue was not the naming since each subgraph is handled seperately so having a global Root counter might cause inconsistent naming based on the order of the subgraphs in the composition configuration.
And this wasn't fixing the issue at all.
So I created this PR to fix the issue.