Implement support for some basic embed options for work sheets via LTI

This commit also fixes an issue with the flash messages being positioned too high and displayed for too long

app/assets/javascripts/editor/participantsupport.js.erb

@@ -172,8 +172,9 @@ CodeOceanEditorRequestForComments = {
     this.createSubmission($('#requestComments'), null, createRequestForComments.bind(this));
 
     $('#comment-modal').modal('hide');
+    $('#question').val('');
     // we disabled the button to prevent that the user spams RFCs, but decided against this now.
     //var button = $('#requestComments');
     //button.prop('disabled', true);
-  },
+  }
 };