Prior to this commit, the `patchValue()` of the `FormGroup` and `FormArray` classes used to throw an exception
when the `value` argument contained a data structure that has `null` or `undefined` as a value for a field
that represents an instance of `FormGroup` or `FormArray` (for `FormControl` it's not a problem, since it
doesn't have nested controls), since the `patchValue()` method tried to iterate over provided values to
match current data structure.
This commit updates the `patchValue()` logic in `FormGroup` and `FormArray` classes to just ignore `null` and
`undefined` values (without any changes to corresponding `FormGroup` and `FormArray` instances). This
behavior looks inline with the `patchValue()` method goal of "doing its best to match the values to the
correct controls" (quote from docs).
Fixes#36672.
Fixes#21021.
PR Close#40534
c9fe455fa2