Remove workaround for Tycho limit-modules issue
Remove the workaround in pom.xml
of the org.eclipse.escet.common.app.framework
project. As https://bugs.eclipse.org/bugs/show_bug.cgi?id=541269 is fixed it shouldn't be needed anymore once we migrate to the Tycho version of Eclipse 2020-06 (note that we can switch Tycho versions without actually upgrading fully to that Eclipse version).