Unable to restrict bucket access by Cognito User Group when importing auth

### Before opening, please confirm:

- [X] I have installed the latest version of the Amplify CLI (see above), and confirmed that the issue still persists.
- [X] I have [searched for duplicate or closed issues](https://github.com/aws-amplify/amplify-cli/issues?q=is%3Aissue+).
- [X] I have read the guide for [submitting bug reports](https://github.com/aws-amplify/amplify-cli/blob/master/CONTRIBUTING.md#bug-reports).
- [X] I have done my best to include a minimal, self-contained set of instructions for consistently reproducing the issue.
- [X] I have removed any sensitive information from my code snippets and submission.

### How did you install the Amplify CLI?

npm

### If applicable, what version of Node.js are you using?

14.15.0

### Amplify CLI Version

8.0.1

### What operating system are you using?

Mac

### Did you make any manual changes to the cloud resources managed by Amplify? Please describe the changes made.

No manual changes made

### Amplify Categories

auth, storage

### Amplify Commands

configure

### Describe the bug

When importing a Cognito User Pool, the option to restrict CRUD actions for storage by User Groups is no longer there.

### Expected behavior

The ability to restrict access to Storage by Cognito User Groups when importing a User Pool.

### Reproduction steps

1. amplify import auth (follow prompts to import existing Cognito User Pool)
2. amplify add storage

### GraphQL schema(s)

N/A

### Log output

N/A

### Additional information

After digging through some of the code it seems in this line:

https://github.com/aws-amplify/amplify-cli/blob/1daf72029bda79645ee95997c40a887741499164/packages/amplify-category-storage/src/provider-utils/awscloudformation/service-walkthroughs/s3-walkthrough.ts#L83

Must be returning an empty list when it should probably return the imported User Pool's groups.

Looking at this line:
https://github.com/aws-amplify/amplify-cli/blob/1daf72029bda79645ee95997c40a887741499164/packages/amplify-cli/src/extensions/amplify-helpers/get-userpoolgroup-list.ts#L7

It seems it gets the user groups from a file from the repo. Which isn't created when importing auth.

Any help would be greatly appreciated!! 🙏

Start with packages/amplify-category-storage/src/provider-utils/awscloudformation/service-walkthroughs/s3-walkthrough.ts at the referenced line, then inspect packages/amplify-cli/src/extensions/amplify-helpers/get-userpoolgroup-list.ts and the imported-auth project files. Reproduce the flow with amplify import auth followed by amplify add storage; done means imported Cognito User Pool groups appear as choices for restricting storage CRUD access.

Written by the indexing model from the issue text.