Add docs for SwitchPresenter

[michael-hawker]

Fixes #409

Docs for Toolkit PR CommunityToolkit/WindowsCommunityToolkit#3379 and CommunityToolkit/WindowsCommunityToolkit#3789 where SwitchPresenter as added.

What changes to the docs does this PR provide?

Adds control doc for SwitchPresenter

PR Checklist

Please check if your PR fulfills the following requirements:

• Correctly picked the right branch to base the change off (master for new features, live for typos/improvements)
• For new pages, used the provided template
• For new features, added an entry in the Table of Contents
• Ran against a spell and grammar checker
• Contains NO breaking changes

Other information

[opbld31]

Docs Build status updates of commit adfa8d4:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/controls/SwitchPresenter.md	✅Succeeded	View
docs/toc.md	✅Succeeded	View

For more details, please refer to the build report.

Note: Broken links written as relative paths are included in the above build report. For broken links written as absolute paths or external URLs, see the broken link report.

For any questions, please:

• Try searching the docs.microsoft.com contributor guides
• Post your question in the Docs support channel

[opbld31]

Docs Build status updates of commit 2a990b9:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/controls/SwitchPresenter.md	✅Succeeded	View
docs/toc.md	✅Succeeded	View

For more details, please refer to the build report.

Note: Broken links written as relative paths are included in the above build report. For broken links written as absolute paths or external URLs, see the broken link report.

For any questions, please:

• Try searching the docs.microsoft.com contributor guides
• Post your question in the Docs support channel

[opbld30]

Docs Build status updates of commit 59f60c5:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/controls/SwitchPresenter.md	✅Succeeded	View
docs/toc.md	✅Succeeded	View

For more details, please refer to the build report.

Note: Broken links written as relative paths are included in the above build report. For broken links written as absolute paths or external URLs, see the broken link report.

For any questions, please:

• Try searching the docs.microsoft.com contributor guides
• Post your question in the Docs support channel