Resize favicon when tabs are too small

[cezaraugusto]

• 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).

Auditors: @bbondy

Fix #7656

Test Plan:

• Have 20 tabs
• Resize window
• Favicon should be resized when window is too small

[bbondy]

that's nice 👍