software/slapos-sr-testing: install theia test egg

fixes 794185d0

software/slapos-sr-testing/software.cfg

@@ -184,7 +184,7 @@ eggs =
   ${slapos.test.jupyter-setup:egg}
   ${slapos.test.nextcloud-setup:egg}
   ${slapos.test.turnserver-setup:egg}
-  ${slapos.test.theia-setup:setup}
+  ${slapos.test.theia-setup:egg}
   ${slapos.test.cloudooo-setup:egg}
   ${slapos.test.dream-setup:egg}
   ${backports.lzma:egg}