fix: basic repair context-menu script broken

[ACTCD]

fix #743

In old Safari browser.menus.remove just failed silently for non-existent menu item, but in the latest version it rejects the promise, causes failed functional due to unhandled throw.

userscripts/src/ext/background/main.js

Lines 201 to 204 in bca043a

	// since it's not possible to get a list of currently active menu items
	// on update, all context-menu items are cleared, then re-added
	// this is done to ensure fresh code changes appear
	await browser.menus.removeAll();

Since all menu items are actually deleted every time, sessionStorage related logic is not necessary. So simply delete it.

Paths ending in / corresponding to different Match patterns are expected and can be avoided at the user level. There no need to handle it at the extension level, so the relevant logic is deleted.

Anyway, it's just a simple fix to get it basically working again.
But this feature needs to be completely redesigned and refactored.

• New context menu architecture design #453