chore: CartItem product connection resolvers updated.

[kidunot89]

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What does this implement/fix? Explain your changes.

Update CartItem product and variation connections to use PostObjectConnectionResolver

Does this close any currently open issues?

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Any relevant logs, error output, GraphiQL screenshots, etc?

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Any other comments?

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Where has this been tested?

• WooGraphQL Version: …
• WPGraphQL Version: …
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[codeclimate]

Code Climate has analyzed commit c80b4c0 and detected 2 issues on this pull request.

Here's the issue category breakdown:

Category	Count
Style	2

The test coverage on the diff in this pull request is 100.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 74.9% (-2.0% change).

View more on Code Climate.