[Feature Request]: Add warning when extensions cannot be installed to Extensions > Available tab

[tomasohara]

Is there an existing issue for this?

• I have searched the existing issues and checked the recent builds/commits

What would your feature do ?

It would be good for the UI to indicate that extensions cannot currently be installed because --enable-insecure-extension-access wasn't specified at startup.

from log:
AssertionError: extension access disabled because of command line flags

Proposed workflow

1. Run webui.sh
2. Select [Extension] tab
3. Select [Available] sub-tab

A warning should precede the list of available extensions. Moreover, the [Install] buttons should be grayed out.

Additional information

No response