Replace error message "We ran into a little trouble. It might just be a hiccup. Try again in a bit." for non-admin users under "Manage app requests"

Currently to be able to approve app requests one needs to be an admin/site-admin.

In case the user does not have enough permissions, error "We ran into a little trouble. It might just be a hiccup. Try again in a bit." is shown which is not descriptive and does not highlight actual reason.

The error should be more descriptive and replaced to something like:  “You need to be an admin to see this page.”