[INTERNAL] sap.m.MessageBox: Testsuite sample adjusted
[INTERNAL] sap.m.MessageBox: Testsuite sample adjusted

- The sample was not fully visible on a mobile device,
as a result of the default "allowWrapping: false"
property.
- Now the sample is accessible.

JIRA: BGSOFUIRILA-2505
Change-Id: I2dac336eb64b52defd8a898ca4f9539b172459aa

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