馃崚 dataengines/mpris2: tolerate non-standards compliant players like mpris-proxy
BlueZ mpris-proxy doesn't provide "SupportedUriSchemes" or "SupportedMimeTypes". Since the two properties are not directly used in the media controller widget, show a debug message instead of rejecting the player.
BUG: 466288 FIXED-IN: 5.27.3
(cherry picked from commit 177cf79b)