Remove Dependency on %Studio.SourceControl.Change

Embedded Git has a class extending %Studio.SourceControl.Change. This class is due to be removed from Product and will only be available from CCR. To support clients without the %Studio.SourceControl.Change class natively in IRIS, Embedded Git needs to remove any references to this class. A class extending this should move any class members being inherited to the sub class and then the Extends relationship removed from the class definition. This class is scheduled for removal starting with 2026.3 (can update issue should this change).