test(otlp-grpc-exporter-base): do not use hard-coded version in tests, touch up changelog entries

[pichlermarc]

Which problem is this PR solving?

See test failure in #5068, after we updated the versions, the tests failed because they were hardcoded. This PR fixes this, and also moves some changelog entries to the correct spot (I had put them in bugfix but they belong in the breaking changes section).

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Unit tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.27%. Comparing base (a1442fe) to head (d5d7839).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5069      +/-   ##
==========================================
+ Coverage   93.26%   93.27%   +0.01%     
==========================================
  Files         317      317              
  Lines        8195     8195              
  Branches     1641     1641              
==========================================
+ Hits         7643     7644       +1     
+ Misses        552      551       -1     

see 1 file with indirect coverage changes