Mark created Pholio mockups as new objects to fix empty Feed transaction entries

Summary:
When creating a Pholio mockup, setIsCreateTransaction(true) to avoid an empty Transaction field in the Feed and avoid strncmp() complaining about a null value being passed.

This is very similar to T15659 about Differential Diffs.

ERROR 8192: strncmp(): Passing null to parameter #1 ($string1) of type string is deprecated at [/var/www/html/phorge/phorge/src/applications/policy/query/PhabricatorPolicyQuery.php:314]

Closes T15679

Test Plan:

1. Create a new Pholio mockup via /pholio/create/
2. Go to /feed/transactions/query/all/
3. Compare entries in the Transaction column before (empty ones) and after (no empty ones) applying the patch.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T15679

Differential Revision: https://we.phorge.it/D25600