In my refactor #22137 to move variable service to the document level shadow root was not handled correctly. This causes amp analytics in shadow mode to throw and not send analytics pings.

Plan to fix this, and hopefully prevent similar issues in the future:

• Revert ♻️Move VariableService to doc level #22137
• Add support for shadow root testing in integration tests
• Create shadow root test for amp-analytics
• Reimplement variable service refactor