feat(grpc): support for oneof types

[meskill]

Summary:
Briefly describe the changes made in this PR.

Issue Reference(s):
Fixes #1912

Build & Testing:

• I ran cargo test successfully.
• I have run ./lint.sh --mode=fix to fix all linting issues raised by ./lint.sh --mode=check.

Checklist:

• I have added relevant unit & integration tests.
• I have updated the documentation accordingly.
• I have performed a self-review of my code.
• PR follows the naming convention of <type>(<optional scope>): <title>

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.30%. Comparing base (f421e5a) to head (1f89957).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1983      +/-   ##
==========================================
+ Coverage   82.28%   82.30%   +0.01%     
==========================================
  Files         174      174              
  Lines       17804    17828      +24     
==========================================
+ Hits        14650    14673      +23     
- Misses       3154     3155       +1     

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[github-actions]

Action required: PR inactive for 2 days.
Status update or closure in 5 days.

[tusharmath]

Moving to draft, since this is the base PR. Feel free to change the status once it's ready.

[meskill]

superseded by #1992