[INTERNAL] sap.m.MessageBox: Accessibility test page enhanced
[INTERNAL] sap.m.MessageBox: Accessibility test page enhanced

- Checkbox is added, in order to easily toggle
compact/cozy mode.
-  More comprehensible title is used.

JIRA: BGSOFUIRILA-2423
Change-Id: If8fd5a92662bebac399a76adb56fb88e417e8b30

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