Remove invalid GEMA codes

[ROpdebee]

Some CISAC ISWCNet entries display invalid GEMA codes of the form AS[long string of hex characters], e.g. AS7C630C8E643C8C1C0C. I'm not sure what these mean or why they show up, but they're not present in GEMA's own results. As far as I know, they're always accompanied by a valid code. Since these are invalid, we should remove them from the pasted codes outright. Some editors already do this manually, but some also don't, which means they need to be removed again afterwards (e.g. Edit #91164124).

I remember sending an e-mail to GEMA many months ago, asking what these codes are and why they're showing up on ISWCNet, but I've never received a reply. They're possibly ignoring me because I wrote to them in English. @kellnerd could you (or someone else who speaks German) try to contact them in German and see if they reply to you? If they still don't reply, I might end up sending an e-mail to CISAC themselves, but I think getting a reply from them is even less likely.

[ROpdebee]

I found a solo invalid GEMA code on T-311.319.059-9, but that ISWC is not even present in the GEMA database. Strange.

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Another interesting observation: The sourcedb for these is 315, not 35 as for the correct GEMA codes.