fix(select): handle corner case of adding options via a custom directive

Under specific circumstances (e.g. adding options via a directive with `replace: true` and a
structural directive in its template), an error occurred when trying to call `hasAttribute()` on a
comment node (which doesn't support that method).
This commit fixes it by filtering out comment nodes in the `addOption()` method.

Fixes #13874
Closes #13878