Update js-clients to process action responses

[garymardell]

The response from an upsert action was not being properly handled by useAction and therefore the data was not being returned to the user. This was because the action.hasReturnType looks like:

{
  "... on CreatePostResult": { hasReturnType: false },
  "... on UpdatePostResult": { hasReturnType: true },
}

in the useAction processResult it would just check if action.hasReturnType is truthy and if so use mutationData.result. However in this case the value is truthy but an object not a boolean value.

We already have the utility inside the api-client-core to process the action results (which is used both by the core action runner and background actions) which handles this case correctly so this updates the code to use that instead.

PR Checklist

• Important or complicated code is tested
• Any user facing changes are documented in the Gadget-side changelog
• Any immediate changes are slated for release in Gadget via a generated package dependency bump
• Versions within this monorepo are matching and there's a valid upgrade path

[garymardell]

The vite tests fail on this PR too as its trying to use the version of api-client-core that would be released by this PR...

[airhorns]

Hm, thats new! If you don't bump the version in this PR, does it work ok?

[airhorns]

Changes look good to me

[garymardell]

If you don't bump the version in this PR, does it work ok?

No, because the package doesn't export the function for react client to use without version bump. Going to merge a PR that exposes the function and bumps version first and then will rebase this.