Remove title attributes: the Menus screen when no-js

[afercia]

See related #24766 and all the following tickets about title attributes.

On the "Menus" screen, only when JavaScript is off, some no-JS compatibility links appear and they have title attributes.

I'd suggest to remove the title attributes and use plain text (hidden with screen-reader-text) for the arrows, and just show the "Edit" link. See in the screenshot below, before and after the patch.

Tried to give the "Edit" link just a basic styling, after all it's shown just when JS is off and maybe there's no need for further styling. No visual changes when JavaScript is on.

[afercia]

The proposed patch also removes some mixed spaces/tabs in the CSS.

[afercia]

Refreshed patch to use aria-label attributes instead of text hidden with .screen-reader-text.

[afercia]

In 36016:

Accessibility: Remove title attributes and improve accessibility on the "no-js" Menus screen.

When JavaScript is off, the reorder menu item and Edit menu item links now use aria-label
attributes instead of title attributes.

Fixes #35134.