setUninstallURL length update

[patrickkettner]

Hiya folks!
There was a an issue on our mailing list recently, where folks brought up hitting the string limit in setUninstallURL. I pushed a CL to update this to 1023. For some reason I was thinking this was a chrome specific API, so I did not think to bring it to the group first. Apologizes for that. I dug into support elsewhere and found that Safari apparently did not enforce any length from what I could tell, and Firefox had to (up-until recently) same limit of 255. I submitted a PR to mozilla as well.