Update SqlInstrumentation ActivitySource name

[utpilla]

Changes

• Update SqlInstrumentation ActivitySource name to "OpenTelemetry.Instrumentation.SqlClient"

• Appropriate CHANGELOG.md updated for non-trivial changes

[codecov]

Codecov Report

Merging #3435 (25c2c3e) into main (be588bd) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #3435      +/-   ##
==========================================
- Coverage   86.29%   86.27%   -0.02%     
==========================================
  Files         263      263              
  Lines        9542     9545       +3     
==========================================
+ Hits         8234     8235       +1     
- Misses       1308     1310       +2     

Impacted Files	Coverage Δ
...qlClient/Implementation/SqlActivitySourceHelper.cs	100.00% <100.00%> (ø)
...metryProtocol/Implementation/ActivityExtensions.cs	94.50% <0.00%> (-1.10%)	⬇️