[FIX] sap.f.ShellBar: Unnecessary Second title truncation fixed
[FIX] sap.f.ShellBar: Unnecessary Second title truncation fixed

The problem:
The second title gets truncated no matter there was enough space to show
the whole title

The root cause:
Rounding was not taken into account from element scrollWidth resulting
in sub-pixel width applied to the element which triggered truncation

The solution:
Use getBoundingClientRect where available + add 1 pixel to the
calculated width which compensates for zoom levels

Change-Id: I3b6ef133150d3cf3bc5abc34fbb3814d9e64cdc5

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