We have a check when running Cypress tests to ensure that no new `.js`
files are added under Cypress folder. This PR moves this check to a
separate JS file. There's another check that does some ADS compliance,
which I'll port in a follow-up PR.
Why am I hitting on this? One, to move away from `umani/changed-files`
workflow, which has randomly failed for us in the past, and id doesn't
do so much special for us anyway. Two, this workflow is the last usage
of `APPSMITH_CI_TEST_PAT` secret, so I should be able to remove that
secret as well. One less secret.
