Merge branch '50020-fe-allow-email-notifications-to-be-disabled-for-all-users-of-a-group' into 'master'

UI for disabling group/project email notifications

Closes #50020

See merge request gitlab-org/gitlab-ce!30961

(cherry picked from commit 1068483f)

7699a87e UI for disabling group/project email notification
bad143ff Rename canChangeEmailsDisabled to canDisableEmails
38b3f9ec Hide emails_disabled checkbox if disabled in group
5e1fc2f5 Apply suggestion to...
bcd5cee9 Addressed review feedback
d602fc12 Minor fixes for gitlab.pot
1ee32758 Update permissions documentation
43c87103 Vue file prettified
e5ec00ce Apply suggestion to app/views/shared/notifications/_button.html.haml
e2de0db9 Disable the subgroup checkbox
dbd7fcbd Add checked to emails_disabled group settings