Remove default logger name

[lalitb]

Changes

As per the specs - https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/logs/sdk.md#logger-creation

In the case where an invalid name (null or empty string) is specified, a working Logger MUST be returned as a fallback rather than returning null or throwing an exception, its name SHOULD keep the original invalid value, and a message reporting that the specified value is invalid SHOULD be logged.

So changed the implementation to create the instrumentation scope with empty name if provided and log the warning.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 79.5%. Comparing base (6ca7881) to head (09dd87f).

Files with missing lines	Patch %	Lines
opentelemetry-sdk/src/logs/log_emitter.rs	50.0%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2316   +/-   ##
=====================================
  Coverage   79.5%   79.5%           
=====================================
  Files        123     123           
  Lines      21258   21258           
=====================================
  Hits       16907   16907           
  Misses      4351    4351           

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[cijothomas]

lets add a test for this?