Added Stream over ReadOnlySequence<byte>

[paulomorgado]

PR Checklist

• [X] Created a feature/dev branch in your fork (vs. submitting directly from a commit on main)
• [X] Based off latest main branch of toolkit
• [X] PR doesn't include merge commits (always rebase on top of our main, if needed)
• [X] Tested code with current supported SDKs
• [ ] New component
  • [ ] Pull Request has been submitted to the documentation repository instructions. Link:
  • [ ] Added description of major feature to project description for NuGet package (4000 total character limit, so don't push entire description over that)
• [X] Tests for the changes have been added (for bug fixes / features) (if applicable)
• [ ] Header has been added to all new source files (run build/UpdateHeaders.bat)
• [X] Contains NO breaking changes
• [X] Every new API (including internal ones) has full XML docs
• [X] Code follows all style conventions

Other information

This PR adds a AsStream() extension method to ReadOnlySequence<byte> similarly to the same method for Memory<byte> and ReadOnlyMemory<byte>.