Following recent similar actions done for entities.
Required at this stage to provider better & cleaner helpers
for common user and permission actions to built out permission testing.
- Added testing check to buffer stop/clear on streaming output due to
interference during tests.
- Made content-disposition header a little safer in download responses.
- Also aligned how we check for testing environment.
Page-related items added on drafts could be visible in certain scenarios
since the applied permissions query filters would not consider
page draft visibility.
This commit alters queries on related items to apply such filtering.
Included test to cover API scenario.
Thanks to @haxatron for reporting.
