Remove duplicate global propagator setup

[ArunRajjj]

Summary

Remove the duplicate global propagator setup from the gRPC client example.

InitTracer() already configures the global propagator, so the additional
configuration in main() is redundant.

Testing

Reviewed the resulting diff; only the redundant propagator setup was removed.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: ArunRajjj / name: Arunraj (e52858c)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.69%. Comparing base (e4232d8) to head (e52858c).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4655      +/-   ##
==========================================
- Coverage   86.70%   86.69%   -0.00%     
==========================================
  Files         525      525              
  Lines       20596    20596              
==========================================
- Hits        17856    17854       -2     
- Misses       2740     2742       +2     

see 1 file with indirect coverage changes

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[marcalff]

Thanks for the contribution.

Closing, duplicate of #4654