[FIX] sap.m.OverflowToolbar: Fixed flickering on input livechange
[FIX] sap.m.OverflowToolbar: Fixed flickering on input livechange

Problem: When there is an sap.m.Input element inside OverflowToolbar
and also a hidden element is bound with same model property,
and livechange is turned on, there is some flickering on change.

Solution: We isolated hidden controls from the flex container of the
OverflowToolbar.

Change-Id: I5d628e5630d941d2e8d8c20330b9a2565710781a
BCP: 1980416492

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