Clear all CDM resources when switching to inactive state

[smudri85]

Summary: Clear all CDM resources when switching to inactive state.
Type: Fix
Test Plan: UT/CT, Fullstack
Jira: RDKEMW-19750

[github-actions]

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Type: Feature/Fix/Cleanup
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[Copilot]

Pull request overview

Fixes CDM cleanup on state transitions by ensuring all per-session and per-client CDM bookkeeping is cleared when the SessionServer switches to the inactive state, preventing stale session state from being used after resources are torn down.

Changes:

• Clear m_mediaKeysClients and m_sessionInfo alongside m_mediaKeys during CdmService::switchToInactive().
• Ensure CDM session/client state does not outlive the active lifecycle of the SessionServer.

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[github-actions]

Coverage statistics of your commit:
Congratulations, your commit improved lines coverage from: 84.2% to 84.3%
Functions coverage stays unchanged and is: 92.6%

[github-actions]

Coverage statistics of your commit:
Congratulations, your commit improved lines coverage from: 84.2% to 84.3%
Functions coverage stays unchanged and is: 92.6%