Fix lal dictionary leak for phenomX

Description

There was a memory leak when the lal dictionary argument was passed as NULL. We free the memory if this happens.

API Changes and Justification

Backwards Compatible Changes

• This change introduces no API changes
• This change adds new API calls

Backwards Incompatible Changes

• This change modifies an existing API
• This change removes an existing API

If any of the Backwards Incompatible check boxes are ticked please provide a justification why this change is necessary and why it needs to be done in a backwards incompatible way.

Review Status

@david-keitel tested the fix in a separate branch