Refactor legacy Storybook stories

[benbowler]

Feature Description

We have a number of Storybook stories in the legacy format, in the folder /stories/. These stories lead to inconsistent structure in the way stories show when built. Updating them will make our stories clear and consistent across all modules and components.

Some examples:

1. The Account Chooser and Settings stories, if updated, could show in the global or components group rather than at the root level:

2. Older modules stories should be updated so that they show in the Modules folder and their stories can be sorted alphabetically:

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Acceptance criteria

Implementation Brief

Test Coverage

QA Brief

Changelog entry