Replace "You're invited to join" title to "Matrix user page" title on pages, that links to mxid

**Describe the bug**
Now link to my Matrix user at https://matrix.to/#/@murz:ru-matrix.org shows the page with "You're invited to join" title - this looks like invitation for join to some public room or community, instead of some "User info" page.

**Expected behavior**
I know, that "User profiles" is not implemented yet in Matrix, but simply change title "You're invited to join" to something like "Matrix user page" will be much better. And already below we can add some info "Matrix id of this user", and actions buttons like "Start new chat with this user".

Start at the Matrix user URL shown in the issue and trace the page that currently renders the "You're invited to join" title. Confirm how that view handles a user MXID, then update the user-page wording and verify the link still opens the intended Matrix user page.

Written by the indexing model from the issue text.