Clip commonly seen labels used for display names to prevent Unicode spam

Unfortunately a pretty common spam/annoyance online is putting "spam"
via abusing Unicode symbols - which is used for multilingual support -
in display names. This typically results in an unreadable word jumble in
our UI, which looks bad.

So I decided to put a stop to that by clipping some labels that could be
used for this crap. I didn't cover *everything* yet, but this at least
prevents these idiots from showing up in the completion menu, the room
member list and as authors for messages.

src/app/qml/UserDetailDialog.qml

@@ -63,6 +63,7 @@ Kirigami.Dialog {
                     level: 1
                     Layout.fillWidth: true
                     font.bold: true
+                    clip: true // Intentional to limit insane Unicode in display names
 
                     elide: Text.ElideRight
                     wrapMode: Text.NoWrap