fix typo in function name, cleanup unused args (#317)

Signed-off-by: Jess Frazelle <github@jessfraz.com>

src/lib/testHelpers.ts

@@ -10,7 +10,7 @@ class MockEngineCommandManager {
   startNewSession() {}
   waitForAllCommands() {}
   waitForReady = new Promise<void>((resolve) => resolve())
-  sendModellingCommand() {}
+  sendModelingCommand() {}
   sendSceneCommand() {}
 }