When a user pushed to a GitLab EE license that had an expired license,
it would fail with one of two errors:

In the current GitLab 13.1 branch it would show:

```
undefined method `license_message' for LicenseHelper:Module
```

However, previous versions would show:

```
undefined method `full_sanitizer' for Gitlab::GitAccess:Class
```

The latter error occurred because the view helper strip_tags only works
in a view. We now explicitly define `strip_tags` to use the same
sanitizer.

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/217031