refactor Resource::SanitizeValue method to be more readable

[kiapanahi]

Code clean-up for the SanitizeValue method on the Resource type.

[mic-max]

LGTM thanks!

[codecov]

Codecov Report

Merging #2761 (d9c27d5) into main (66ad39d) will decrease coverage by 0.16%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #2761      +/-   ##
==========================================
- Coverage   83.75%   83.59%   -0.17%     
==========================================
  Files         251      246       -5     
  Lines        8835     8724     -111     
==========================================
- Hits         7400     7293     -107     
+ Misses       1435     1431       -4     

Impacted Files	Coverage Δ
src/OpenTelemetry/Resources/Resource.cs	95.34% <100.00%> (-0.49%)	⬇️
....TelemetryHttpModule/TelemetryHttpModuleOptions.cs	0.00% <0.00%> (-90.00%)	⬇️
....AspNet.TelemetryHttpModule/TelemetryHttpModule.cs	0.00% <0.00%> (-5.27%)	⬇️
...entation.AspNet/TracerProviderBuilderExtensions.cs
...umentation.AspNet/Implementation/HttpInListener.cs
...rumentation.AspNet/AspNetInstrumentationOptions.cs
...ry.Instrumentation.AspNet/AspNetInstrumentation.cs
...Implementation/AspNetInstrumentationEventSource.cs
...emetry.Api/Internal/OpenTelemetryApiEventSource.cs	82.35% <0.00%> (+5.88%)	⬆️
... and 1 more