[Exporter.Geneva] Add exponential histogram support for otlp protobuf format

[vishweshbankwar]

Fixes #1378

Changes

Adds support for exporting exponential histograms when OTLP protobuf encoding is enable for metric exporter.

For significant contributions please make sure you have completed the following items:

• Appropriate CHANGELOG.md updated for non-trivial changes
• Design discussion issue #
• Changes in public API reviewed

[codecov]

Codecov Report

Attention: Patch coverage is 92.15686% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 64.22%. Comparing base (71655ce) to head (e603c0b).
Report is 233 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1705      +/-   ##
==========================================
- Coverage   73.91%   64.22%   -9.69%     
==========================================
  Files         267       35     -232     
  Lines        9615     3567    -6048     
==========================================
- Hits         7107     2291    -4816     
+ Misses       2508     1276    -1232     

Flag	Coverage Δ
unittests-Exporter.Geneva	64.22% <92.15%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...eneva/Metrics/OtlpProtobuf/FieldNumberConstants.cs	80.00% <ø> (ø)
...a/Metrics/OtlpProtobuf/ProtobufSerializerHelper.cs	100.00% <100.00%> (ø)
...eva/Metrics/OtlpProtobuf/OtlpProtobufSerializer.cs	90.65% <91.66%> (ø)

... and 249 files with indirect coverage changes

[vishweshbankwar]

Received approval from component owner.