Enhance ExtractDataKeyFromMetaKeyd to work with MetaTensor

[AdamaSorho]

Fixes #7562 .

Description

This pull request improves ExtractDataKeyFromMetaKey, enabling it to extract keys from a MetaTensor.

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• [ x] New tests added to cover the changes.
• [x ] Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• [ x] Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[ericspod]

Suggested change

	if isinstance(d[self.meta_key], MetaTensor):
	# meta tensor
	meta = d[self.meta_key].meta
	else:
	# meta dict
	meta = d[self.meta_key]
	meta: dict[str, Any]
	if isinstance(d[self.meta_key], MetaTensor):
	# meta tensor
	meta = d[self.meta_key].meta # type: ignore
	else:
	# meta dict
	meta = d[self.meta_key]

This might be needed to get around the type issue.