[FIX] sap.m.Tree: ACC - do not announce the expanded information for leaf node
[FIX] sap.m.Tree: ACC - do not announce the expanded information for
leaf node

Change-Id: Ibfa1dc02df199a066dfc32cbf5735a0c408f56cd
BCP: 1770071587

SAP/openui5,cschuff/openui5,SQCLabs/openui5,olirogers/openui5,olirogers/openui5,olirogers/openui5,nzamani/openui5,SAP/openui5,cschuff/openui5,nzamani/openui5,SQCLabs/openui5,SAP/openui5,SQCLabs/openui5,nzamani/openui5,cschuff/openui5,SAP/openui5