Donatewiki forms currently pass various unneeded and/or empty URL parameters to payments. We should clean these up similar to how we did for banners.
Example url from donatewiki:
https://payments.wikimedia.org/index.php/Special:GatewayFormChooser ?utm_source=fr-redir.default%7Edefault%7Edefault%7Edefault%7Econtrol.cc &utm_medium=spontaneous &utm_campaign=spontaneous &utm_key= &referrer= &language=en &country=US &payment_method=cc &payment_submethod= &recurring=false &gateway= &ffname= &amountGiven= ¤cy_code=USD &frequency=onetime &amount=3
Example url from a banner:
https://payments.wikimedia.org/index.php/Special:GatewayFormChooser ?payment_method=cc &recurring=false ¤cy_code=USD &uselang=en &country=US &amount=3 &utm_medium=sitenotice &utm_campaign=test &utm_source=B1819_0701_mlWW_dsk_p1_lg_template.no-LP.cc &utm_key=0