[temp] When bubblewrap fixes, remove key signing workaround

[jgw96]

This bug GoogleChromeLabs/bubblewrap#693 causes an issue where, since we were using the same generated password for both the keyPassword and storePassword, the build fails. I have implemented a workaround in the latest commit 10429c5 , but when Bubblewrap fixes this issue, we should remove the workaround