chore(sdk-metrics): remove accidental export of the SDK Meter class

[pichlermarc]

Which problem is this PR solving?

Looks like I missed the export of the SDKs Meter during the SDK clean up in #3197. This PR removes the export for Meter as the API's Meter interface is supposed to be used instead.

Related #3158

Type of change

Please delete options that are not relevant.

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

How Has This Been Tested?

• Existing tests

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

Merging #3243 (52b8436) into main (5818129) will increase coverage by 0.01%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3243      +/-   ##
==========================================
+ Coverage   93.28%   93.30%   +0.01%     
==========================================
  Files         202      202              
  Lines        6599     6599              
  Branches     1384     1384              
==========================================
+ Hits         6156     6157       +1     
+ Misses        443      442       -1     

Impacted Files	Coverage Δ
...-trace-base/src/platform/node/RandomIdGenerator.ts	93.75% <0.00%> (+6.25%)	⬆️