Fix endless redirections when accessing user OAuth applications when they are disabled

## What does this MR do?

This MR fixes a bug where the browser would be redirect endlessly when attempting to access the user's OAuth applications when an admin has disabled this system-wide setting.

## Are there points in the code the reviewer needs to double check?

I assume disabling the nav button is better than showing a page that says, "OAuth applications are disabled by the admin."

## Why was this MR needed?

Lots of users were confused when they hit endless redirect errors.

## What are the relevant issue numbers?

#14770 

See merge request !4525