feat: accordion: adds rendercontentalways prop managed by expanded

[dkilgore-eightfold]

SUMMARY:

• Adds renderContentAlways prop to Accordion, improving keyboard and assistive tech usability config upstream
• Adds UTs
• Updates Stories

We useEffect to first check if renderContentAlways is true. If it is, we set shouldRender to true and skip the rest of the checks. If renderContentAlways is false, we then check if expanded is true. If it is, we set shouldRender to true and clear any existing timeout. If expanded is false, we start a timeout that sets shouldRender to false after 400ms, affording time for the animation to complete.

accordion.mp4

JIRA TASK (Eightfold Employees Only):

ENG-86284

CHANGE TYPE:

• Bugfix Pull Request
• Feature Pull Request

TEST COVERAGE:

• Tests for this change already exist
• I have added unittests for this change

TEST PLAN:

Pull the PR branch and run yarn and yarn storybook. Verify the Accordion stories behave as expected.

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