refactoring: Move nested modules

[alisdair]

When applying module moved statements by iterating through modules in state, we previously required an exact match from the moved statement's from field and the module address. This permitted moving resources directly inside a module, but did not recur into module calls within those moved modules.

This commit moves that exact match requirement so that it only applies to moved statements targeting resources. In turn this allows nested modules to be moved.

As of this commit, we are relying on the logic in ModuleInstance.MoveDestination() to control whether or not a given module instance is relevant to a moved statement. This method will return a false match result if the move statement doesn't apply:

terraform/internal/addrs/move_endpoint_module.go

Lines 461 to 468 in cd72771

	// MoveDestination considers a an address representing a module
	// instance in the context of source and destination move endpoints and then,
	// if the module address matches the from endpoint, returns the corresponding
	// new module address that the object should move to.
	//
	// MoveDestination will return false in its second return value if the receiver
	// doesn't match fromMatch, indicating that the given move statement doesn't
	// apply to this object.

Fixes #30197

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