fix: change Environment Var parsing to not throw FormatException (part1)

[TimothyMothra]

Towards #3690

According the OTel spec:

For variables accepting an enum value, if the user provides a value the SDK does not recognize, the SDK MUST generate a warning and gracefully ignore the setting.

In this PR, I changed the TryParse to NOT throw FormatException and instead log to EventSource.
Unit tests and documentation will be fixed in a follow up PR to keep the PR a reasonable size.

Changes

• ConfigurationExtensions
  remove throw FormatException and instead log a Warning in EventSource.
• temporarily disable unit tests.

Please provide a brief description of the changes here.

For significant contributions please make sure you have completed the following items:

• Appropriate CHANGELOG.md updated for non-trivial changes
• Design discussion issue #
• Changes in public API reviewed

[reyang]

Should value be touched here? (I guess no)

[TimothyMothra]

good catch! it's an out param so it needs to be set, but it's already been set by the Try method in the if statement.

[reyang]

LGTM.

[codecov]

Codecov Report

Merging #4095 (a399c88) into main (10389e3) will decrease coverage by 0.11%.
The diff coverage is 25.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4095      +/-   ##
==========================================
- Coverage   85.67%   85.57%   -0.11%     
==========================================
  Files         289      289              
  Lines       11256    11261       +5     
==========================================
- Hits         9644     9637       -7     
- Misses       1612     1624      +12     

Impacted Files	Coverage Δ
.../OpenTelemetry/Internal/ConfigurationExtensions.cs	87.50% <0.00%> (-12.50%)	⬇️
...nTelemetry/Internal/OpenTelemetrySdkEventSource.cs	80.46% <100.00%> (+0.31%)	⬆️
...porter.OpenTelemetryProtocol/OtlpMetricExporter.cs	72.72% <0.00%> (-13.64%)	⬇️
...tation/OpenTelemetryProtocolExporterEventSource.cs	85.00% <0.00%> (-10.00%)	⬇️
...tpListener/Internal/PrometheusCollectionManager.cs	73.62% <0.00%> (-2.20%)	⬇️
...ZPages/Implementation/ZPagesExporterEventSource.cs	62.50% <0.00%> (+6.25%)	⬆️