[CONFIGURATION] File configuration - exemplar filter

[marcalff]

Fixes # (issue)

Changes

Please provide a brief description of the changes here.

• Implement the missing exemplar_filter property, not implemented for C++
• Follow up on: Add .meter_provider.exemplar_filter property opentelemetry-configuration#131

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

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.96%. Comparing base (e5173e4) to head (60235ba).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3837   +/-   ##
=======================================
  Coverage   89.96%   89.96%           
=======================================
  Files         225      225           
  Lines        7170     7170           
=======================================
  Hits         6450     6450           
  Misses        720      720           

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[lalitb]

Thanks.