Fix mvn build error

[gru11]

Fixes building error when building via terminal

-------------------------------------------------------------------------------
Test set: net.openchrom.xxd.identifier.supplier.cdk.converter.MoleculeImage_Test
-------------------------------------------------------------------------------
Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.679 s <<< FAILURE! -- in net.openchrom.xxd.identifier.supplier.cdk.converter.MoleculeImage_Test
net.openchrom.xxd.identifier.supplier.cdk.converter.MoleculeImage_Test.testAspirin -- Time elapsed: 0.678 s <<< ERROR!
org.eclipse.swt.SWTException: Invalid thread access
	at org.eclipse.swt.SWT.error(SWT.java:4950)
	at org.eclipse.swt.SWT.error(SWT.java:4865)
	at org.eclipse.swt.SWT.error(SWT.java:4836)
	at org.eclipse.swt.widgets.Display.error(Display.java:1211)
	at org.eclipse.swt.widgets.Display.createDisplay(Display.java:962)
	at org.eclipse.swt.widgets.Display.create(Display.java:946)
	at org.eclipse.swt.graphics.Device.<init>(Device.java:132)
	at org.eclipse.swt.widgets.Display.<init>(Display.java:800)
	at org.eclipse.swt.widgets.Display.<init>(Display.java:791)
	at org.eclipse.swt.widgets.Display.getDefault(Display.java:1545)
	at org.eclipse.chemclipse.support.ui.workbench.PreferencesSupport.isDarkTheme(PreferencesSupport.java:46)
	at net.openchrom.xxd.identifier.supplier.cdk.ui.converter.ImageConverter.createImage(ImageConverter.java:110)
	at net.openchrom.xxd.identifier.supplier.cdk.ui.converter.ImageConverter.smilesToImage(ImageConverter.java:63)
	at net.openchrom.xxd.identifier.supplier.cdk.converter.MoleculeImage_Test.testAspirin(MoleculeImage_Test.java:31)

[gru11]

cant find the error in the pipeline, but on my local machine building works successfully.