Add GH_SCALAR_ARRAY to argument_mod

[mo-alistairp]

Are there any linked Issues or Pull Requests?

No response

Brief description

stfc/PSyclone/issues/1312 introduces ScalarArrays to be used in LFRic (see stfc/PSyclone#3101). In order for LFRic to recognise this new argument type (GH_SCALAR_ARRAY) we need to add the type to argument_mod.F90. This issue will address that

Further details of the issue.

No response

[james-bruten-mo]

[Automatic Update]

The Code Review deadline for the Spring 2026 has passed. As this issue does not have a linked pull request it has been removed from the milestone. Please review this issue and either select a new milestone or close it as appropriate. Please contact @MetOffice/ssdteam if you think there has been an error.

Thanks

[mo-alistairp]

This was implemented in #223