Partner Portal: add react-query mutation to handle assigning multiple licenses flow

[yashwin]

Proposed Changes

This PR adds a new react-query mutation to handle assigning multiple licenses flow.

Testing Instructions

No testing is needed on this PR. The test instructions will be provided in the upcoming PR where this will be used. You could just review the code changes here.

Pre-merge Checklist

• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?

Related to 1203126240279377-as-1203156900348731

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-46893

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-46893&env=jetpack

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[rcanepa]

I see a significant overlap between useLicenseIssuing and useIssueMultipleLicenses, which makes me wonder if there is an opportunity to abstract the commonalities.

Is useIssueMultipleLicenses expected to work for a single license too? If so, could we replace useLicenseIssuing with useIssueMultipleLicenses everywhere?

[rcanepa]

The new function looks good to me. However, I haven't tried it, but I know we will once we connect it to the new product catalog page.

Therefore, I approve it since this won't be visible to current users and won't introduce any regression.