Remove dependency which is not needed (#1344).

Author: kbirken

code/languages/org.iets3.opensource/languages/org.iets3.analysis.base/models/structure.mps

@@ -8,7 +8,6 @@
   <imports>
     <import index="4kwy" ref="r:657c9fde-2f36-4e61-ae17-20f02b8630ad(org.iets3.core.base.structure)" />
     <import index="tpck" ref="r:00000000-0000-4000-0000-011c89590288(jetbrains.mps.lang.core.structure)" />
-    <import index="hm2y" ref="r:66e07cb4-a4b0-4bf3-a36d-5e9ed1ff1bd3(org.iets3.core.expr.base.structure)" />
   </imports>
   <registry>
     <language id="c72da2b9-7cce-4447-8389-f407dc1158b7" name="jetbrains.mps.lang.structure">