Merge branch '361125-webhook-encrypted-tokens-frontend-support-validations' into 'master'

Add presence validation to URL and URL mask items on webhook form

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/102720



Merged-by: Phil Hughes <me@iamphill.com>
Approved-by: Sharmad Nachnolkar <snachnolkar@gitlab.com>
Approved-by: Libor Vanc <5022246-lvanc@users.noreply.gitlab.com>
Approved-by: Phil Hughes <me@iamphill.com>
Co-authored-by: Justin Ho <hduong@gitlab.com>