[Admin] Shipping category update

[loicginoux]

Summary

This PR follows the work started on https://github.com/solidusio/solidus/pull/5718 where Shipping categories creation was implemented. This PR is for updating a shipping category. The issue is https://github.com/solidusio/solidus/issues/5720 This PR includes the creation code as well because it was forked from the branche on https://github.com/solidusio/solidus/pull/5718, so I'll keep this one in draft until the creation PR is merged. This PR follows the code for editing tax categories from this PR https://github.com/solidusio/solidus/pull/5697, I pretty much copy and adapt the code and added a spec (missing for tax categories edition). Talking about copying/duplicating code, should these basic crud actions be refactored to avoid duplication for other models ?

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