perf: Optimize has_more_than_n_keys function and BatchTraceProcessor

[tongshu1943]

Feature Description

Implemented performance optimizations in two key areas of the codebase:

1. Replaced inefficient key counting method in has_more_than_n_keys function with a more efficient approach
2. Optimized the BatchTraceProcessor class to improve trace and span export performance

Specific Improvements

1. Modified has_more_than_n_keys function to use len(obj) directly instead of iterating through keys
2. Optimized _export_batches method to reduce queue checks and improve batching logic
3. Added tests to verify the optimized functions work correctly

Technical Implementation

• Dictionary key counting: Using len(obj) directly is more efficient than iterating through all keys
• Trace batch processing: Reduced the number of queue checks and improved the batching logic
• Both optimizations maintain existing behavior without introducing regressions
• Added comprehensive test coverage for the optimized functions

Testing

• Added test file test_has_more_than_n_keys.py to verify the optimized function
• All tests pass, confirming the optimizations work correctly
• All type checks and lint checks pass