Fix WebView hanging input

[mallexxx]

Task/Issue URL: https://app.asana.com/0/1177771139624306/1206990108527681/f

Description:

• fixes the mouse event queue overflow issue when loading websites (see https://app.asana.com/0/0/1207061219313301/f)
• the fix is done by proxying NSTrackingArea delegate and suppressing mouse events while Web View is loading

Steps to test this PR:

1. Add the attached snippet to WindowControllersManager.swift:125
   WindowControllersManager.swift.zip
2. Create a bookmark to twitter.com on your bookmark bar
3. Click the bookmark on the home tab, wait until ❗️ that‘s it appears in the log and verify mouse input is working, repeat
4. Repeat opening the bookmark when another website is open

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Internal references:

Pull Request Review Checklist
Software Engineering Expectations
Technical Design Template
Pull Request Documentation

[samsymons]

Seems good to me pending CI getting back to a green state, looks like a recent commit broke some compilation, I tested before it was added though.

I'm no longer able to reproduce the bug (neither by using your provided changes, or when testing by hand), and I spent some time smoke testing other sites, including testing in a slow network environment via Network Link Conditioner, to make sure that we aren't introducing weird behaviour when the web view takes a long time to load.

I'll approve this, feel free to merge once it's green. Great work! Next step here is on me to try and get this happening in a standalone project that we can send to Apple.

[samsymons]

LGTM, new changes are working well 👍

I tested on regular conditions, poor networks, etc., tried to find a way to break webview interaction but couldn't, and the bug is gone in all of my testing. Nice work!