Switch version from function to string in otelmongo

[lcorinna]

refactor(otelmongo): change Version() func to const Version string
Part of #8272

[linux-foundation-easycla]

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• ✅ login: lcorinna / name: Dimaaaa (1270d76, 23365fa)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.3%. Comparing base (ac3d638) to head (23365fa).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #8340     +/-   ##
=======================================
- Coverage   82.3%   82.3%   -0.1%     
=======================================
  Files        193     191      -2     
  Lines      13769   13765      -4     
=======================================
- Hits       11334   11330      -4     
  Misses      2030    2030             
  Partials     405     405             

Files with missing lines	Coverage Δ
...mongodb.org/mongo-driver/mongo/otelmongo/config.go	100.0% <100.0%> (ø)

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