feat(configuration): add sampler parsing

[MikeGoldsmith]

Which problem is this PR solving?

Fixes #6290

RC3 spec requires sampler configuration via YAML files and environment variables. Currently missing:

• Type models for probability/development and composite/development samplers
• YAML sampler parsing in FileConfigFactory
• Environment variable sampler parsing (OTEL_TRACES_SAMPLER, OTEL_TRACES_SAMPLER_ARG)

Short description of the changes

Type Models (tracerProviderModel.ts):

• Added ProbabilitySampler, CompositeSampler, RuleBasedSampler interfaces
• Extended Sampler union with probability/development and composite/development

YAML Parsing (FileConfigFactory.ts):

• Added parseSampler() function supporting all sampler types
• Recursive parsing for nested samplers (parent_based.root, etc.)
• Integrated into setTracerProvider()

Environment Variable Parsing (EnvironmentConfigFactory.ts):

• Added setSampler() function supporting:
  • always_on, always_off, traceidratio
  • parentbased_always_on, parentbased_always_off, parentbased_traceidratio
• Parses OTEL_TRACES_SAMPLER_ARG for ratio values

Tests:

• 5 new env var sampler tests
• 1 YAML fixture test (samplers.yaml)
• Validates all basic and parent-based sampler types

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Unit tests for env var sampler parsing (always_on, always_off, traceidratio, parentbased variants)
• Integration test for YAML sampler parsing
• Existing kitchen-sink.yaml includes complex sampler configurations

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated (CHANGELOG)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.62%. Comparing base (34e7d91) to head (11956e5).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6409      +/-   ##
==========================================
+ Coverage   95.59%   95.62%   +0.03%     
==========================================
  Files         361      361              
  Lines       11595    11688      +93     
  Branches     2683     2719      +36     
==========================================
+ Hits        11084    11177      +93     
  Misses        511      511              

Files with missing lines	Coverage Δ
...ages/configuration/src/EnvironmentConfigFactory.ts	99.54% <100.00%> (+0.03%)	⬆️
...al/packages/configuration/src/FileConfigFactory.ts	97.79% <100.00%> (+0.21%)	⬆️
...es/configuration/src/models/tracerProviderModel.ts	100.00% <ø> (ø)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.