Compare SSH_DOMAIN when parsing submodule URLs (#12753)

Compare SSH_DOMAIN when parsing submodule URLs (#12753)

Right now we only compare the hostname from a submodule with the prefixURL it is viewed from to check if the submodule is hosted on the same Gitea instance. This adds an additional check to compare it against SSH_DOMAIN as well since the same Gitea instance might have a different hostname for SSH and if the submodule uses that hostname we should also detect that and link to the proper DOMAIN value.

Fixes #12747, #9756