[INTERNAL] sap.m.MessagePopover: Accessibility test page enhanced
[INTERNAL] sap.m.MessagePopover: 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: I7317e4ad1335d5d0de983a920f9995e181e1841a

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