Issue #3442399 by catch: Remove deprecated code/bc layers from workspaces module

core/modules/workspaces/src/Form/WorkspaceFormInterface.php

core/modules/workspaces/src/WorkspaceAssociation.php

.../modules/workspaces/src/WorkspaceAssociationInterface.php

core/modules/workspaces/src/WorkspaceManager.php

core/modules/workspaces/src/WorkspaceManagerInterface.php

core/modules/workspaces/src/WorkspaceMerger.php

core/modules/workspaces/src/WorkspaceOperationFactory.php

core/modules/workspaces/src/WorkspacePublisher.php

.../tests/src/Kernel/WorkspaceAssociationDeprecationTest.php