Fix `land/sftgif_ti-u-hxy-u@fx:afx` `land/rootd_ti-u-hxy-lnd@fx:afx` for UKESM1-3

[mo-laurenboon]

The above variables currently fail when attempting to produce with UKESM1-3-LL with an error of the type Unable to produce MIP requested variable "sftgif_ti-u-hxy-u" for "CMIP7_land": No data available for "1851"; please check run_bounds regardless of the run bounds given.

First glance at the ancil suggests that the required stash is present. This should be investigated and resolved where possible.