Fix zoom level on browser restore

[diracdeltas]

and remove deprecated zoom level site setting.

fix #7832

Test Plan:

1. launch clean instance of brave
2. go to example.com and change the zoom level
3. close brave
4. reopen brave
5. example.com should load with the previous zoom setting

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Test Plan:

[bridiver]

muon should is supposed to handle this automatically so I think we should fix the problem there. If we need something on the browser-laptop side we should do it in tabs.js because all of the webview methods are deprecated (especially getter methods because they are sync ipc)

[diracdeltas]

closing in favor of brave/muon@7baccbe