UI layer test name lacks information on what it's testing

This UI layer test name doesn't reveal much, but has a docstring which explains what it is testing for: https://github.com/DiamondLightSource/httomo/blob/c7e399d09f56a238e4c731c5f66857047f7f4752/tests/test_ui_layer.py#L93-L94

The information in the docstring about testing the handling of `OutputRef` by the UI layer should be moved to the test name.

Open tests/test_ui_layer.py around lines 93–94 and read the existing test name and docstring. Rename the test so its name states that the UI layer handles OutputRef, preserving the existing test behavior; done means the test name communicates the behavior without relying on the docstring.

Written by the indexing model from the issue text.