DNN-7454 - added logic to disable button on form submit.
DNN-7454 - added logic to disable button on form submit.

It doesn't matter if the button doesn't get-reactivated because the web form posts back and re-renders the button if its invalid.

bdukes/Dnn.Platform,moshefi/Dnn.Platform,RichardHowells/Dnn.Platform,janjonas/Dnn.Platform,mitchelsellers/Dnn.Platform,robsiera/Dnn.Platform,RichardHowells/Dnn.Platform,dnnsoftware/Dnn.Platform,svdv71/Dnn.Platform,janjonas/Dnn.Platform,moshefi/Dnn.Platform,RichardHowells/Dnn.Platform,yiji/Dnn.Platform,bdukes/Dnn.Platform,SCullman/Dnn.Platform,dnnsoftware/Dnn.Platform,nvisionative/Dnn.Platform,dnnsoftware/Dnn.Platform,valadas/Dnn.Platform,mitchelsellers/Dnn.Platform,janjonas/Dnn.Platform,nvisionative/Dnn.Platform,dnnsoftware/Dnn.Platform,wael101/Dnn.Platform,wael101/Dnn.Platform,bdukes/Dnn.Platform,valadas/Dnn.Platform,JoshuaBradley/Dnn.Platform,svdv71/Dnn.Platform,abukres/Dnn.Platform,EPTamminga/Dnn.Platform,SCullman/Dnn.Platform,RichardHowells/Dnn.Platform,SCullman/Dnn.Platform,yiji/Dnn.Platform,moshefi/Dnn.Platform,EPTamminga/Dnn.Platform,valadas/Dnn.Platform,robsiera/Dnn.Platform,valadas/Dnn.Platform,JoshuaBradley/Dnn.Platform,nvisionative/Dnn.Platform,abukres/Dnn.Platform,mitchelsellers/Dnn.Platform,mitchelsellers/Dnn.Platform,wael101/Dnn.Platform,abukres/Dnn.Platform,bdukes/Dnn.Platform,svdv71/Dnn.Platform,JoshuaBradley/Dnn.Platform,valadas/Dnn.Platform,dnnsoftware/Dnn.Platform,mitchelsellers/Dnn.Platform,EPTamminga/Dnn.Platform,robsiera/Dnn.Platform,yiji/Dnn.Platform