Currently the code in the `FormGroupDirective` assumes that the shape of the underlying `FormGroup` never
changes and `FormControl`s are not replaced with other types. In practice this is possible and Forms code
should be able to process such changes in FormGroup shape.
This commit adds extra check to the `FormGroupDirective` class to avoid applying FormControl-specific to
other types.
Fixes#13788.
PR Close#40829