Fix issues with custom pause menu binds

This patch fixes issues where custom binds would incorrectly respect keyboard layout, similar to !2295 (merged). The two fixes involves:

• If the menu button is bound to something that maps to a key, pressing the key that maps to it would also trigger that bind. This can be triggered on Dvorak by binding QWERTY B and pressing the layouted B (N on QWERTY) on the keyboard.
• Changing keybinds now makes sure that it actually binds to the QWERTY layout instead of the native one. This is merely done as a precaution, since while ev_keydown should trigger first and thus prioritize QWERTY, I haven't yet confirmed if that's the case on all OSes yet.