Fix exception in Transaction Log after renaming Pholio Mock image: Call to undefined method PholioImageSequenceTransaction::renderHandleLink()

Summary:
Replace call to undefined renderHandleLink() with renderHandle().

Additionally, pass head_key($new) instead of key($new). This might not be needed strictly speaking for this very issue but should not harm either as several images in a mock can be renamed at once.

EXCEPTION: (Error) Call to undefined method PholioImageSequenceTransaction::renderHandleLink() at [<phorge>/src/applications/pholio/xaction/PholioImageSequenceTransaction.php:32]

Closes T15680

Test Plan:

• Rename the title of an image in a Pholio mock.
• Go to /feed/transactions/query/all/ which now renders instead of showing an error, and shows two entries:
• user renamed an image (newname.jpg) from oldname.jpg to newname.jpg. and user updated an image's (newname.jpg) sequence.

(However, separate T15679 will still show up in the error log after this change.)

Reviewers: O1 Blessed Committers, speck

Reviewed By: O1 Blessed Committers, speck

Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T15680

Differential Revision: https://we.phorge.it/D25482