The telegram app id is org.telegram.desktop, and its appstream
component id is org.telegram.desktop.desktop, which we did not
properly handle (we special cased the app-id-ends-with-desktop case
and then did not remote .desktop). This replaces that with a more
approach that *always* matches the whole app id as prefix, and then
replaces a ".desktop" in the suffix part only.
Closes: #1593
Approved by: alexlarsson