otelgin: Clean Route setup in otelgin HTTP instrumentation

[arshukla98]

Description:-

The intention of this PR is to resolve the issue #6976 .

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: arshukla98 / name: Aditya Shukla (ca98185, 31c9c5c, 2b3df82)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.8%. Comparing base (b0c0319) to head (849db54).

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #6982   +/-   ##
=====================================
  Coverage   75.8%   75.8%           
=====================================
  Files        207     207           
  Lines      19494   19493    -1     
=====================================
+ Hits       14783   14784    +1     
+ Misses      4275    4274    -1     
+ Partials     436     435    -1     

Files with missing lines	Coverage Δ
...umentation/github.com/gin-gonic/gin/otelgin/gin.go	92.9% <100.0%> (-0.1%)	⬇️

... and 3 files with indirect coverage changes

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