fix: avoid invoking onCompletion handler twice for non-service errors

[thisisabhash]

Issue #, if available:
onCompletion handler of FaceLivenessDetectionView was being invoked twice for non-service events like close button, timing out etc.

Description of changes:
Non-service events like Close button, Timing out etc. invoke onCompletion handler twice:

• once during the event itself - it then makes a call to close websocket
• the websocket connection closure again invokes onCompletion handler
  This is now being invoked only for service/web socket related events.

Check points: (check or cross out if not relevant)

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 28.44%. Comparing base (c6efb44) to head (a966f78).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...iews/Liveness/FaceLivenessDetectionViewModel.swift	0.00%	4 Missing ⚠️
...Liveness/Views/Liveness/LivenessStateMachine.swift	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #214      +/-   ##
==========================================
- Coverage   28.86%   28.44%   -0.43%     
==========================================
  Files          58       58              
  Lines        3104     3094      -10     
==========================================
- Hits          896      880      -16     
- Misses       2208     2214       +6     

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[numpolpol]

The feature is working correctly on the customer app. However, please re-check the completion logic: when the app is sent to the background (e.g., via the Home button or Control Center) while the camera is open, it's still triggering completion multiple times.