[IFT] Fix parsing of the callback ID if it is greater than 999

Found that `com.intellij.AbstractBundle.getMessage` applies the formatting to the parameters passed as a `Number`. For example, it translates 1032 int to "1,032" string. And then `toInt` method fails to parse it.
Better to use String value as ID for callbacks to avoid this problem.

GitOrigin-RevId: 95a667a35f6107ec71df0da26892541d1d964b98

python/python-features-trainer/src/com/jetbrains/python/ift/lesson/essensial/PythonOnboardingTourLesson.kt

@@ -216,7 +216,7 @@ class PythonOnboardingTourLesson :
     }
   }
 
-  private fun getCallBackActionId(@Suppress("SameParameterValue") actionId: String): Int {
+  private fun getCallBackActionId(@Suppress("SameParameterValue") actionId: String): String {
     val action = getActionById(actionId)
     return LearningUiManager.addCallback { invokeActionForFocusContext(action) }
   }