feat(ui): Add modular section fetch status indicators to sidebar navigation

[NityamPareek]

Summary

Implements section fetch status tracking in the left navigation panel of the Usage & Adoption telemetry module with modular architecture:

• Section Status Indicators:
  • Idle: No icon when fetch has not been triggered
  • Loading: Circular progress indicator (ft.ProgressRing) when section telemetry is being fetched
  • Success: Green tick (ft.Icons.CHECK_ROUNDED, #16A34A) when fetch completes without errors
  • Error: Red tick (ft.Icons.CHECK_ROUNDED, #DC2626) when fetch completes with one or more card errors
• Modular Component Design:
  • SectionStatus Enum and SectionStatusIndicator / create_section_status_indicator in flet_ui/components/section_status_indicator.py
  • BaseSectionView in flet_ui/views/sections/base_section_view.py providing shared status state, card registration, error evaluation, and thread-safe UI execution
  • Refactored all 4 section views (IdentityLicensingView, AppUsageAdoptionView, SecurityComplianceGovernanceView, EcosystemIntegrationsAutomationView) to inherit from BaseSectionView
  • Integrated reactive status updates in UsageAdoptionDashboardView