[macOS] Improve geolocation provider test reliability

[samsymons]

Task/Issue URL: https://app.asana.com/1/137249556945/task/1214132819416367?focus=true
Tech Design URL:
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Description

This PR improves reliability of geolocation provider tests by making sure that the test waits for the appropriate events to complete before asserting any state.

Testing Steps

1. Check that CI is green

Impact and Risks

What could go wrong?

Quality Considerations

Notes to Reviewer

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Internal references:

Definition of Done | Engineering Expectations | Tech Design Template

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Note

Low Risk
Low risk because it only adjusts unit test coordination logic; main risk is altering test ordering assumptions and potentially masking a real concurrency issue if the new gating is incorrect.

Overview
Improves reliability of GeolocationProviderTests by changing the multi-webview pause scenario to wait until both web views have received the first location before pausing webView2 and publishing the second location.

This replaces a subscription-history-based trigger with explicit per-webview receipt flags, reducing race conditions in testWhenOneWebViewGeolocationIsPausedThenAnotherWebViewContinuesReceivingLocationUpdates().

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