Help text for ui-base 'Allow App Installation' is deficient

### Current Behavior

The help text for ui-base Allow App Installation ends with the text:
"It is recommended to not use this option if you are"
Which leaves us all on tenterhooks worrying about whether it should be enabled or not.

### Expected Behavior

The help text should be sufficient that we do not lie abed at night worrying about whether we have configured it correctly.

### Steps To Reproduce

_No response_

### Environment

- Dashboard version: 1.28.0
- Node-RED version:
- Node.js version:
- npm version:
- Platform/OS:
- Browser:

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate