Clicking the button opens the browser, on the "new topic" page inside
the help forum. Web can now correctly read the build number of the
client since https://github.com/ppy/osu-web/pull/12478 so I see
no reason not to.
Minimal effort implementation. Stemmed from discussion in
https://discord.com/channels/90072389919997952/299846395031060480/1437368033734561792.
Not really interested in putting more effort into this at this point, if
this is not considered acceptable then just close the PR and this can be
revisited more properly at a later date.
For package-managed solutions that set `OSU_EXTERNAL_UPDATE_STREAM`
(which overrides the config value), we should not allow the user to
change the release stream themselves.