adding missing colorbars to surface plots

[BernardClaxton]

Describe the bug

surface plots:

• UM Surface grid_surface_snow_amount
• LFRic Surface northward_wind_at_10m
• UM Surface surface_microphysical_snowfall_rate
• UM Surface surface_downward_longwave_flux
• LFRicUM Surface atmosphere_mass_content_of_cloud_ice
• UM Surface atmosphere_mass_content_of_cloud_liquid_water
• UM Surface surface_microphysical_rainfall_rate
• UM Surface toa_direct_shortwave_flux
• LFRic Surface surface_net_longwave_flux_radiative_timestep
• LFRic Surface grid_surface_upward_sensible_heat_flux
• LFRic Surface toa_direct_shortwave_flux
• LFRic Surface toa_upward_longwave_flux_radiative_timestep
• UM Surface surface_downward_shortwave_flux

difference plots:

• Surface surface_net_shortwave_flux difference (UM - LFRic)
• Surface grid_surface_snow_amount difference (UM - LFRic)
• Surface number_of_lightning_flashes_in_column difference (UM - LFRic)
• Surface surface_microphysical_rainfall_rate difference (UM - LFRic)
• Surface turbulent_mixing_height difference (UM - LFRic)
• Surface atmosphere_mass_of_air_per_unit_area difference (UM - LFRic)
• Surface radar_reflectivity_at_1km_above_the_surface difference (UM - LFRic)
• Surface surface_downward_longwave_flux difference (UM - LFRic)
• Surface surface_downward_shortwave_flux difference (UM - LFRic)
• Surface atmosphere_mass_content_of_cloud_ice difference (UM - LFRic)
• Surface atmosphere_mass_content_of_cloud_liquid_water difference (UM - LFRic)
• Surface atmosphere_mass_content_of_water_vapor difference (UM - LFRic)

How to reproduce

Steps to reproduce the behaviour:

Expected behaviour

Environment

• Version: [e.g. from cset --version]
• Browser (if UI issue): [e.g. Chrome, Firefox]