fix(configuration): merge service name from OTEL_SERVICE_NAME instead of replacing all resource attributes

[maryliag]

When we had a value in OTEL_SERVICE_NAME it was wrongly replacing the entire attributes list, instead of just the service name value.
This PR fixes that and add a test for this case

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.40%. Comparing base (315c0f0) to head (9756598).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6162   +/-   ##
=======================================
  Coverage   95.40%   95.40%           
=======================================
  Files         317      317           
  Lines        9427     9430    +3     
  Branches     2180     2183    +3     
=======================================
+ Hits         8994     8997    +3     
  Misses        433      433           

Files with missing lines	Coverage Δ
...ages/configuration/src/EnvironmentConfigFactory.ts	99.06% <100.00%> (+<0.01%)	⬆️

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[JacksonWeber]

LGTM!