[DMN Designer] Display a message showing that DMN1.1 is not supported on Kogito channels

DMN1.1 is currently not supported by the client-side marshaller used by DMN editor kogito runtime distribution.

Goals:
Provide an error message on Kogito channels when a DMN1.1 file is opened. To check if a DMN file is 1.1, look for xmlns="http://www.omg.org/spec/DMN/20151101/dmn.xsd". If xmlns="http://www.omg.org/spec/DMN/20180521/MODEL/" is present, then the file is DMN1.2 and should be opened normally. The namespace prefix is optional depending on the construct of the whole model; the check should look for any namespace definition (prefixed with a local name or the default namespace) containing non-DMN1.2 URLs (as there is also DMN1.3 around now too).

Acceptance criteria:
Message is correctly displayed when a DMN1.1 file is opened.