build: drop unused tonic server deps

[tisonkun]

This closes #2665

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.1%. Comparing base (cd9bbcf) to head (243445d).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2666   +/-   ##
=====================================
  Coverage   79.1%   79.1%           
=====================================
  Files        122     122           
  Lines      22562   22562           
=====================================
+ Hits       17861   17862    +1     
+ Misses      4701    4700    -1     

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[tisonkun]

@cijothomas may I ask when is the next release expected out? I'd make a corresponding expectation for upgrading my project later or patch it right now.

[cijothomas]

~2 weeks (https://github.com/open-telemetry/opentelemetry-rust/milestone/19)
if there is enough demand, we can always do a .1 release for OTLP Exporter any time.