fix: suppress SLF4J startup warning in Tycho test runtime

Set -Dslf4j.internal.verbosity=ERROR in the Tycho Surefire argLine.
SLF4J 2.x uses ServiceLoader for provider discovery, which doesn't
work across OSGi classloaders — the warning is cosmetic (SLF4J
defaults to NOP regardless). This is the documented suppression
mechanism since SLF4J 2.0.10.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: joaodinissf

com.avaloq.tools.ddk.xtext.test/pom.xml

@@ -24,7 +24,7 @@
           <useUIThread>false</useUIThread>
           <useUIHarness>true</useUIHarness>
           <forkedProcessTimeoutInSeconds>${test.timeout}</forkedProcessTimeoutInSeconds>
-          <argLine>-Dlogback.configurationFile="${runtime.logbackConfig}" ${test.javaOptions}</argLine>
+          <argLine>-Dslf4j.internal.verbosity=ERROR -Dlogback.configurationFile="${runtime.logbackConfig}" ${test.javaOptions}</argLine>
           <appArgLine>-pluginCustomization ${runtime.pluginCustomization}</appArgLine>
           <product>${runtime.product}</product>
           <application>org.eclipse.ui.ide.workbench</application>