[FIX] MessagePage: failing visual test corrected
[FIX] MessagePage: failing visual test corrected

The id of the required button used to be wrong.

Change-Id: I72bfde7422b9faab693ab58c9759f64662501c28

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