tracker-extract: Update panasonic cameras' RAW images mimetype
This used to be image/x-panasonic-raw, but changed in https://gitlab.freedesktop.org/pi-r-p/shared-mime-info/commit/8cbd1a38b0bb0a62020984572fd5a33233245239
Keep up with this change, which avoids us from going through the generic image handler (GStreamer) and making life terrible to people with those cameras. Reported by jurf on IRC.