test: Add comprehensive test coverage for OCICohereChatOptions, AzureEmbeddingsOptions, WeaviateVectorStoreOptions classes

[alxkm]

Added extensive test coverage for configuration options classes:
OCICohereChatOptions:

• Builder pattern validation (minimal fields, null handling)
• Deep copy verification and immutability testing
• Boundary value testing (min/max values for temperature, topP, etc.)
• Collection handling (empty lists, null setters)
• State transition testing

AzureEmbeddingsOptions:

• Multiple input handling and order preservation
• Options override behavior
• Different metadata modes
• Concurrent request isolation
• Empty input edge cases

WeaviateVectorStoreOptions:

• Input validation with proper error messages
• Special character and whitespace handling
• State preservation during partial failures
• Case sensitivity verification
• Default value behavior

These tests improve robustness by covering edge cases, boundary conditions, and ensuring proper immutability/deep copying behavior that prevents reference sharing bugs in production.