fix: screen events and autocapture should ignore keyboard window

[ioannisj]

💡 Motivation and Context

Original thread: https://posthog.slack.com/archives/C0113360FFV/p1733238766585229
Ticket: https://posthoghelp.zendesk.com/agent/tickets/21072

Problem

It seems that we were unintentionally capturing view controllers belonging to the keyboard window when sending $screen events. While this might not be a significant issue under normal circumstances, for applications that are message- or form-heavy, this behavior could result in inflated autocapture event volumes.

Fix

• Updated logic to ignore any UIView or UIViewController that belongs to the keyboard window
• Added a similar logic got $autocapture events + some minor improvements

💚 How did you test it?

Sample project

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.