[hosting] Revert obsoletion of OpenTelemetryBuilder

[CodeBlanch]

Changes

• Reverts obsoletion of OpenTelemetryBuilder

Details

This was causing a bit of friction with F# (#5265 (comment)) and Azure Monitor distro.

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• Appropriate CHANGELOG.md files updated for non-trivial changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.42%. Comparing base (6250307) to head (10bf225).
Report is 194 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5571      +/-   ##
==========================================
+ Coverage   83.38%   85.42%   +2.04%     
==========================================
  Files         297      282      -15     
  Lines       12531    12216     -315     
==========================================
- Hits        10449    10436      -13     
+ Misses       2082     1780     -302     

Flag	Coverage Δ
unittests	?
unittests-Solution-Experimental	85.20% <ø> (?)
unittests-Solution-Stable	85.37% <ø> (?)

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

Files	Coverage Δ
...lemetry.Extensions.Hosting/OpenTelemetryBuilder.cs	100.00% <ø> (ø)
...ensions.Hosting/OpenTelemetryServicesExtensions.cs	100.00% <ø> (ø)

... and 78 files with indirect coverage changes