[CT-1804] Add --favor-state as param in click CLI

[jtcohen6]

Context: #5859 (comment)

[jtcohen6]

Copying from #6617

[Tech debt] Inconsistent implementation

Also, the way --favor-state was implemented is parallel to --defer, but different from most of our other flags since v1.0:

dbt-core/core/dbt/flags.py

Lines 117 to 118 in 20c95a4

	DEFER_MODE = env_set_truthy("DBT_DEFER_TO_STATE")
	FAVOR_STATE_MODE = env_set_truthy("DBT_FAVOR_STATE")

(Namely, the argparse default is set based on the flag, rather than the other way around!)

dbt-core/core/dbt/main.py

Lines 504 to 515 in 20c95a4

	def _add_favor_state_argument(*subparsers):
	for sub in subparsers:
	sub.add_optional_argument_inverse(
	"--favor-state",
	enable_help="""
	If set, defer to the state variable for resolving unselected nodes, even if node exist as a database object in the current environment.
	""",
	disable_help="""
	If defer is set, expect standard defer behaviour.
	""",
	default=flags.FAVOR_STATE_MODE,
	)

Let's just solve for this when we move these flags/etc into the new CLI (#6585). We can always add back-compat for the older env vars + flag names — since, in the meantime, some users might add code to their projects like {{ flags.FAVOR_STATE_MODE }}.