[INTERNAL] model.Context: Restrict isPreliminary() to sap.suite.ui.generic
[INTERNAL] model.Context: Restrict isPreliminary() to sap.suite.ui.generic

Change-Id: Iafe359d4ea3baa7bd99ae888c30f95cc80b41035

cschuff/openui5,SAP/openui5,SAP/openui5,SAP/openui5,cschuff/openui5,SAP/openui5,cschuff/openui5