Show Hand Cursor when hovering on Images in MarkdownTextBlock

[avknaidu]

Issue: #1836

PR Type

What kind of change does this PR introduce?

Feature

What is the current behavior?

Shows Selection Cursor on Hover

What is the new behavior?

Shows Hand Cursor on Hover. Also updated docs.

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• Docs have been added/updated which fit documentation template. (for bug fixes / features)
• Tests for the changes have been added (for bug fixes / features) (if applicable)
• Sample in sample app has been added / updated (for bug fixes / features)
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• Header has been added to all new source files (run build/UpdateHeaders.bat)
• Contains NO breaking changes

Other information