* Enable Unit tests for PreviewPane Test Assemblies in CI
* Added Preview handlers unit tests project back
* throw for Svg to debug tests
* Removed failing test
* Removed throw statement
* Added MD unitests in yml
* Run ui tests on STA thread
* Throw svg to debug failing tests
* Updated test adaptor
* Removed failing test to validate CI
* throw svg failing test with full stack trace
* Check if mock stream is causing the issue
* narrow down the failing tests code - 1
* narrow down the failing tests code -2
* dispose all controls
* Restore SVg preview control
* Update test adaptor and dependency to latest
