feat(Stepper): adds custom error list for the top of the form

[mattprinold]

Hey, I just made a Pull Request!

Adds a custom error list component for the stepper form. This shows at the top of the form and captures both internal and input errors in the form.

fixes #21476

✔️ Checklist

• A changeset describing the change and affected packages. (more info)
• Added or updated documentation
• Tests for new functionality and regression tests for bug fixes
• Screenshots attached (for UI changes)
• All your commits have a Signed-off-by line in the message. (more info)

[backstage-goalie]

Changed Packages

Package Name	Package Path	Changeset Bump	Current Version
@backstage/plugin-scaffolder-react	plugins/scaffolder-react	patch	v1.6.2-next.3

[github-actions]

Uffizzi Ephemeral Environment - Virtual Cluster

Your cluster pr-21878 was successfully created. Learn more about Uffizzi virtual clusters
To connect to this cluster, follow these steps:

1. Download and install the Uffizzi CLI from https://docs.uffizzi.com/install
2. Login to Uffizzi, then select the backstage account and project:

uffizzi login

Select an account: 
  ‣ backstage
    jdoe

Select a project or create a new project: 
  ‣ backstage-6783521

3. Update your kubeconfig: uffizzi cluster update-kubeconfig pr-21878 --kubeconfig=[PATH_TO_KUBECONFIG]
   After updating your kubeconfig, you can manage your cluster with kubectl, kustomize, helm, and other tools that use kubeconfig files: kubectl get namespace --kubeconfig [PATH_TO_KUBECONFIG]

Access the backstage endpoint at https://backstage-default-pr-21878-c2479.uclusters.app.uffizzi.com

[mattprinold]

@benjdlambert this keeps failing on the E2E tests though i cant figure out why, could i get some help on this please?

[benjdlambert]

@NeuralEvolution looks like these are failing because of an upstream dependency which has been broken for a few weeks now. Hopefully should be getting solved soon 🤞

frenic/csstype#189
emotion-js/emotion#3141

Will get around to reviewing this today 🎉

[benjdlambert]

Nice! this looks good! 🎉

[mattprinold]

@benjdlambert Thanks, i assume we are waiting for the fix for the e2e tests to merged before we can merge this?

[benjdlambert]

There's a mainline release going out today, but will look at shipping this after that later on Today, and then it will be in the -next release next week :)

[github-actions]

Thank you for contributing to Backstage! The changes in this pull request will be part of the 1.22.0 release, scheduled for Tue, 16 Jan 2024.