fix(client): Prevent inventory opening if NUI is already focused

[tom-osborne]

Description

This PR prevents the inventory opening if another resource already has NUI focus. This was occurring if a user used /tx to open the tx admin, which uses TAB to cycle through the menu.

This issue was raised by Tabarra#1234 in Discord. Ref: https://discord.com/channels/831626422232678481/1045830587694469241

Checklist

• [x] I have personally loaded this code into an updated qbcore project and checked all of its functionality.
• [x] My code fits the style guidelines.
• [x] My PR fits the contribution guidelines.