fix: Can't Delete All Notes

[michael-genson]

What type of PR is this?

(REQUIRED)

• bug

What this PR does / why we need it:

(REQUIRED)

If you add notes to a recipe, save, then remove all of them, save, the notes aren't deleted. I'm not sure why, but I traced it back to our update function - when you pass an empty list of notes to the SQLAlchemy object, it just.... ignores it?

To fix this, I added an explicit check:

def update(self, *args, **kwargs):
    self.__init__(*args, **kwargs)  # this used to be the only line

    for k, v in kwargs.items():
        if hasattr(self, k) and v == []:
            setattr(self, k, v)

What's weird is that it works for other relationships (categories, tools, etc).

Which issue(s) this PR fixes:

(REQUIRED)

Fixes #2756

Testing

(fill-in or delete this section)

Tested through the frontend manually, and added a new backend test.

[p0lycarpio]

Tested on my side and it works. Thanks !

[boc-the-git]

Looks good Michael! :)