[SHIM] Fix string_view mappings between OT and OTel

[chusitoo]

Fixes #3180

Changes

All the conversions opentracing::string_view to nostd::string_view or backwards take the size as second argument.

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

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.86%. Comparing base (fb6fde8) to head (b445e2e).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3181   +/-   ##
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  Coverage   87.86%   87.86%           
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  Files         195      195           
  Lines        6151     6151           
=======================================
  Hits         5404     5404           
  Misses        747      747