RDKBWIFI-460: Fixes and improvements for EasyMesh AP metrics reporting

[vlad-safonov]

Reason for change: this PR contains multiple fixes and improvements to the EasyMesh application's AP metrics reporting

1. Radio MAC matching: Add support for checking against radio's own interface MAC
2. Validation improvements: Fix null checks in prepare_sta_traffic_stats_data and prepare_sta_lins_metrics_data
3. Buffer safety: Fix strncpy buffer size and add null termination
4. Rate calculation: Remove /1000 conversion (rates already in correct units)
5. Error handling: Add malloc failure checks and proper cleanup
6. Cache management: Refresh existing client type cache entries to avoid stale values
7. Fix calculation of RX other (busy_rx - busy_self)
8. Memory initialization: Fix memset sizes for arrays
9. Variable naming: Use correct vap_index variable in client stats storage
10. Loop bounds checking: Add conditions to prevent buffer overruns

Test procedure: AP metrics reports works

Risks: Low
Priority: P2

[vlad-safonov]

I have read the CLA Document and I hereby sign the CLA