SSDM-7583 : ObjectTypeForm - unit tests for more handlers

...s_ng_ui/src/js/components/types/objectType/ObjectType.jsx

...js/components/types/objectType/ObjectTypeHandlerRemove.js

.../components/types/objectType/ObjectTypeHandlerValidate.js

openbis_ng_ui/srcTest/js/common/ComponentState.js

...components/types/objectType/ObjectTypeHandlerLoad.test.js

...nts/types/objectType/ObjectTypeHandlerOrderChange.test.js

...mponents/types/objectType/ObjectTypeHandlerRemove.test.js

...types/objectType/ObjectTypeHandlerSelectionChange.test.js

...onents/types/objectType/ObjectTypeHandlerValidate.test.js