Add a check for multiple stories before rendering the the Stories component in the DocsPage.

[ssabo1]

User Story:
In researching #2385, I couldn't replicate the issue anymore. In talking with @yodasw16, I mentioned another issue that I discovered while researching this thats similar to this one. Dave gave me the permission to submit a PR onto storybook to fix it and said to work with @ssabo1 to create an issue for it when she gets back into office. The issue and the details of the problem are here. storybookjs/storybook#9268

AC:

• Added a check for multiple stories before rendering the the Stories component in the DocsPage. Without this check, unnecessary rendering of the Stories component headline would occur.