Wendelin Telecom: Add 3 KPIs BLER Accessibility Throughput

This MR merges three improvements:

• New KPI computation: BLER, Throughput, Accessibility
• New admin/client UI test coverage for these KPI graphs
• More robust test logic by selecting in_stream by reference (instead of list position)

KPI Formulas

• Throughput

  • DL Throughput = dl_bitrate / duration
  • UL Throughput = ul_bitrate / duration

• BLER

  • DL BLER = dl_retx / dl_tx
  • UL BLER = ul_retx / ul_tx

• Accessibility (combined success rate)

  • Accessibility = (rrc_connection_setup_complete / rrc_connection_request) x (s1_initial_context_setup_response / s1_initial_context_setup_request) x (s1_erab_setup_response / s1_erab_setup_request)

Notes

• Includes missing-value handling in KPI computation
• Keeps tests stable when Data Analysis Line count/order changes
• Test updated: test 6_2 in bt5/erp5_wendelin_telecom_base/TestTemplateItem/portal_components/test.erp5.testWendelinTelecom.py (now selects the in_stream line by reference)