[BUGFIX] Extension Security Report goes green if TER was never fetched

Shows a notice for both the extension security checks as long as
the check for the main repository is not showing an OK state.

As soon as the main repository check is OK, the status of the
extensions will be checked as before.

Change-Id: I41aaa6f4bbb36e32dcb1f734c2b491164a705c76
Resolves: #39043
Releases: 4.7, 4.5
Reviewed-on: https://review.typo3.org/20493
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind