fix: participants and screen sharing tracking in call end analytics - WPB-12199

[caldrian]

WPB-12199 [iOS] Call end - Event and segmentation

Issue

Currently there was an error in the implementation and neither the call participant count nor the screen sharing tracking worked properly.
This PR intents to fix it.

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Checklist

• Title contains a reference JIRA issue number like [WPB-XXX].
• Description is filled and free of optional paragraphs.
• Adds/updates automated tests.

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UI accessibility checklist

If your PR includes UI changes, please utilize this checklist:

• Make sure you use the API for UI elements that support large fonts.
• All colors are taken from WireDesign.ColorTheme or constructed using WireDesign.BaseColorPalette.
• New UI elements have Accessibility strings for VoiceOver.

[github-actions]

Test Results

    1 files      2 suites   2m 21s ⏱️
1 793 tests 1 767 ✅ 26 💤 0 ❌
1 803 runs  1 777 ✅ 26 💤 0 ❌

Results for commit 439b896.

[datadog-wireapp]

Datadog Report

Branch report: fix/call-end-analytics-WPB-12199
Commit report: 44dfdfa
Test service: wire-ios-mono

✅ 0 Failed, 1689 Passed, 26 Skipped, 2m 21.71s Total Time

[netbe]

looks good, should we add a testcase to cover the changes?