connectivity should show if "proxy" is failing #7269
Description
currently, when one is using a proxy, which stopped working (quite usual :), there is no hint, that the proxy is the reason for "cannot connect".
this is esp. bad, as tapping the "cannot connect..." or "connecting..." string opens the connectivity view, see below.
unless it is super-hard to get the proxy-state, i suggest to show sth. as Proxy cannot connect, to begin with, there is no need to make the string translatable (lots of error states are not translated), if it is there, that would be a huge improvement already.
one can also consider to add an additional "proxy line", that is shown even if connection succeeds, however, for the issue at hand, this is not needed, having a better error string is sufficient
this issue is not about adding new api that UI should use