fix: variant clone produces null and undefined values

[mikemurray]

Resolves #6148
Impact: critical
Type: bugfix

Issue

Cloning a variant with that has missing values for title, optionTitle, length, width, height, and weight, would produce null values in the database. This breaks the API.

Solution

Ensure the values valid before inserting them into the database.

Breaking changes

none

Testing

1. Use the reaction admin
2. Clone a variant with options, but don't fill out the fields title, optionTitle, length, width, height, and weight
3. Ensure everything clones correctly
4. Now fill out the missing values and clone a variant that has options
5. See everything clones correctly

[willopez]

Cloning variants now works correctly. However, it's not possible to set the price on a variant. When I set the price and click "Save changes" the prices gets cleared out to an empty string.

[mikemurray]

@willopez I don't think this PR is the ultimate cause of these issues. In the Reaction Admin, I'm seeing missing price/compareAtPrice from the product GQL fragment.

I'm also noticing that the price field for variants with options is an object and not float to represent the price range. This is a bigger problem because a field in GQL is changing between two different types.

[mikemurray]

@willopez Added a ticket about the price issue: #6152

[willopez]

@mikemurray as discussed, we'll handle that issue in a separate PR.

[willopez]

LGTM