[BUU] Enqueue actions to perform at end of reflex

[dacook]

What? Why?

I'm trying to better understand StimulusReflex and doing sort of a health check.

I don't think this will fix https://github.com/openfoodfoundation/openfoodnetwork/issues/12020, but it means sticking a bit closer to convention, and I think things will run slightly smoother.

What should we test?

Just a quick run through of the v3 Bulk Edit Products screen, to test the responsiveness:

• Using filters
• Using different page sizes
• Updating a product

Previously, the success message would sometimes appear before the loading spinner had finished. Now I think it should all happen at the same time.

Release notes

Changelog Category (reviewers may add a label for the release notes):

• [ ] User facing changes
• [ ] API changes (V0, V1, DFC or Webhook)
• [x] Technical changes only
• [ ] Feature toggled

The title of the pull request will be included in the release notes.

Dependencies

Documentation updates