CMIP7: UKCM2: Investigate missing depth coordinates

[mo-laurenboon]

During testing for UKCM2 the variable Omon.zostoga gave the following error "Expected to find exactly 1 'depth' coordinate, but found none." Note that thishas affected this variable at both the daily and monthly frequency.

Additionally, the variable Omon.hfsnthermds gave the similar error "Cube missing coordinate "depth_coord"."

These should be investigated and resolved where possible.

[mo-laurenboon]

Re running the suite with a fresh extract confirms that this issue persists.