I'm trying to replace my Moen shower faucet cartridge but some sort of plastic plate is preventing me from removing the metal locking pin. I can't seem to find anything on YouTube or google that shows any info or videos about this. Any idea what this is doing here and how I get to the locking pin? i tried rotating it, even pushing it to the side,,, but no luck. Attached is a picture for reference. I appreciate any and all help!