Update settings-theme.html

[lvalics]

{{ APP_URL }} to be copied to scripts, without cannot work a script copied into a webpage.

[lvalics]

@all-contributors please add @lvalics for <contributions>

[allcontributors[bot]]

@lvalics

I couldn't determine any contributions to add, did you specify any contributions? Please make sure to use valid contribution names.

[codebanesr]

@lvalics how does {{APP_URL}} get replaced in settings-theme.html ? do we need to run a script ? If so please update the readme

[gharbat]

I think it's being passed here https://github.com/openchatai/OpenChat/pull/166/files @codebanesr

[gharbat]

@all-contributors please add @lvalics for code and docs

[allcontributors[bot]]

@gharbat

I've put up a pull request to add @lvalics! :tada: