ASP.NET and OWIN Instrumentations - fix description for http.server.request.duration metric

[Kielek]

Fixes #.

Changes

Update metric name for AspNet Instrumentation

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

• [ ] Appropriate CHANGELOG.md updated for non-trivial changes
• [ ] Design discussion issue #
• [ ] Changes in public API reviewed

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (71655ce) 73.91% compared to head (9f891a0) 78.61%.
Report is 118 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1538      +/-   ##
==========================================
+ Coverage   73.91%   78.61%   +4.70%     
==========================================
  Files         267       24     -243     
  Lines        9615      477    -9138     
==========================================
- Hits         7107      375    -6732     
+ Misses       2508      102    -2406     

Flag	Coverage Δ
unittests-Instrumentation.AspNet	75.66% <ø> (?)
unittests-Instrumentation.Owin	85.71% <ø> (?)

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see 267 files with indirect coverage changes