Hack: Periodically re-create context menus in Firefox

[yorkxin]

Summary

In Firefox, when context menus were created in MV3, they may disappear unintentionally, even after restart. This is due to a bug in Firefox 1.

This patch introduces a hack which removes and re-creates all the menus every 30 seconds.

Related: #109

Tests

• [ ] Chrome stable (macOS)
• [x] Firefox stable (macOS)
• [ ] Chrome stable (Windows)
• [ ] Firefox stable (Windows)

Optional:

• [ ] Chrome beta (macOS)
• [ ] Firefox beta (macOS)
• [ ] Chrome beta (Windows)
• [ ] Firefox beta (Windows)

[yorkxin]

The menus have once disappeared in some tabs without appearing again. Refreshing the tab and the menus are back, but only in that specific tab.