(Fixes #6673) Update utm params on fxa sign up button
(Fixes #6673) Update utm params on fxa sign up button

ericawright/bedrock,alexgibson/bedrock,flodolo/bedrock,ericawright/bedrock,sgarrity/bedrock,sylvestre/bedrock,pascalchevrel/bedrock,sgarrity/bedrock,pascalchevrel/bedrock,mozilla/bedrock,kyoshino/bedrock,alexgibson/bedrock,MichaelKohler/bedrock,alexgibson/bedrock,sgarrity/bedrock,MichaelKohler/bedrock,mozilla/bedrock,sylvestre/bedrock,sylvestre/bedrock,kyoshino/bedrock,craigcook/bedrock,sgarrity/bedrock,hoosteeno/bedrock,MichaelKohler/bedrock,kyoshino/bedrock,flodolo/bedrock,kyoshino/bedrock,craigcook/bedrock,flodolo/bedrock,pascalchevrel/bedrock,craigcook/bedrock,pascalchevrel/bedrock,ericawright/bedrock,hoosteeno/bedrock,sylvestre/bedrock,ericawright/bedrock,hoosteeno/bedrock,hoosteeno/bedrock,craigcook/bedrock,mozilla/bedrock,MichaelKohler/bedrock,flodolo/bedrock,alexgibson/bedrock,mozilla/bedrock