Update share imported image tests

*Updated share_imported_image module
-Updated tests due to behavior, fixture and config changes
-Updated tests steps
-Added further validation in share_imported_image test
-Added attempted_to_export_shared_imported_image test
-Removed duplicate code

Change-Id: Ib174aa69ee31b230738bce44a0c0c215a3ae08bb
Merge "Update share imported image tests"