loleaflet: calc: corner click cause console error when there is no group

Change-Id: I6d6de4b1126294bbbbdc464cd07441e887221163
Reviewed-on: https://gerrit.libreoffice.org/46779


Reviewed-by: Jan Holesovsky <kendy@collabora.com>
Tested-by: Jan Holesovsky <kendy@collabora.com>

loleaflet/src/control/Control.ColumnHeader.js

@@ -516,6 +516,7 @@ L.Control.ColumnHeader = L.Control.Header.extend({
 		if (pos.x <= rowOutlineWidth) {
 			// empty rectangle on the left select all
 			this._map.sendUnoCommand('.uno:SelectAll');
+			return;
 		}
 
 		var level = this._getGroupLevel(pos.y);

loleaflet/src/control/Control.RowHeader.js

@@ -471,6 +471,7 @@ L.Control.RowHeader = L.Control.Header.extend({
 		if (pos.x > this.getOutlineWidth()) {
 			// empty rectangle on the right select all
 			this._map.sendUnoCommand('.uno:SelectAll');
+			return;
 		}
 
 		var level = this._getGroupLevel(pos.x);