Update required input variables for CMIP7 derived variables

[bouweandela]

Derived variables specify which input variables they need for the derivation. In many cases this will work just fine for CMIP7, but in some cases, this will need to be updated.

For example, the CMIP7 project may not be one of the available options:

ESMValCore/esmvalcore/preprocessor/_derive/amoc.py

Lines 15 to 26 in da81d5f

	def required(project):
	"""Declare the variables needed for derivation."""
	if project == "CMIP5":
	required = [{"short_name": "msftmyz", "mip": "Omon"}]
	elif project == "CMIP6":
	required = [
	{"short_name": "msftmz", "optional": True},
	{"short_name": "msftyz", "optional": True},
	]
	else:
	msg = f"Project {project} can not be used for Amoc derivation."
	raise ValueError(msg)

Or the mip needs to be updated:

ESMValCore/esmvalcore/preprocessor/_derive/et.py

Lines 16 to 18 in 1e53ae9

	def required(project): # noqa: ARG004
	"""Declare the variables needed for derivation."""
	return [{"short_name": "hfls", "mip": "Amon"}]

(would need to be atmos for CMIP7)

Or if, if some of the input variables have a different branding suffix, a special entry for CMIP7 with a branding suffix may need to be added:

ESMValCore/esmvalcore/preprocessor/_derive/vegfrac.py

Lines 25 to 34 in 1e53ae9

	def required(project: str) -> list[Facets]:
	"""Declare the variables needed for derivation."""
	sftlf: Facets = {"short_name": "sftlf", "mip": "fx"}
	if project == "CMIP5":
	sftlf["ensemble"] = "r0i0p0"
	return [
	{"short_name": "baresoilFrac"},
	{"short_name": "residualFrac"},
	sftlf,
	]

(would need to be sftlf: Facets = {"short_name": "sftlf", "branding_suffix": "ti-u-hxy-u", "mip": "atmos"} for CMIP7)