Add ability to parse a Takeout zip file and extract+import bookmarks

[CDRussell]

Task/Issue URL: https://app.asana.com/1/137249556945/project/608920331025315/task/1211197010246723?focus=true

Description

Adds ability to parse a Google Takeout zip file containing exported bookmarks. This PR only adds underlying logic and dev settings to test it; prod UI isn't changed.

Steps to test this PR

Importing a valid file

• Generate a Takeout zip file containing bookmarks. See "Instructions for generating a Takeout zip file" below.
• Fresh install of internal build type
• launch Autofill Dev Settings, and scroll to Import Bookmarks dev settings 🆕
• tap Choose zip file (downloaded from Takeout) and choose the Takeout zip; verify the bookmarks imported using the View Bookmarks button

Importing an invalid file

• tap Choose zip file (downloaded from Takeout) and choose a random other file (either not a Takeout zip or one that doesn't contain bookmarks) and verify it just reports it as invalid as a snackbar

Instructions for generating a Takeout zip file

Tap Launch Google Takeout (normal tab) from Autofill Dev Settings and use this to generate a zip file for testing:
- [ ] sign in
- [ ] Tap on Deselect All
- [ ] Scroll down to Chrome, and check it
- [ ] Optionally, Tap on All Chrome data included and choose only bookmarks
- [ ] Scroll all the way down to the bottom and tap Next step
- [ ] Leave all settings as is, and choose Create export
- [ ] Wait a few seconds, then refresh the page until you see Your latest export shows the export you just created (at the top of the page)
- [ ] Tap Download and confirm you want to save it

[CDRussell]

• Wire bookmarks import dialog / flow into BookmarksActivity #6909
• Add web message listener for js call from bookmark import #6837
• UI for bookmarks import flow #6836
• Add webflow for importing bookmarks from Google #6707
• Add ability to parse a Takeout zip file and extract+import bookmarks #6820 👈 (View in Graphite)
• Add feature flag for importing bookmarks using Google Takeout #6706
• develop

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[cmonfortep]

Posting review. Moving into testing. I will report after that.

[cmonfortep]

All good with testing 👍

Approving, but would like to validate the proposed approach around reading the extracted file, or if this is something you already validated.

[cmonfortep]

didn't approve 😅