LPS-39321 Add methods to be able to pop only the desired system event
LPS-39321 Use the new methos to prevent to remove unwanted system events from the stack
LPS-39321 Small refactoring, the special cases where the services are not annotated do not care about the class pk. Added convenince method to simply call those, avioding confusion why we have 0 at one place and valid class pk at a different place