KPO Maintain backward compatibility for execute_complete and trigger run method

[pankajastro]

In #37279 I introduce periodic logging of the container.
During the process, I also changed a few event Dict key names
and that is problematic for someone extending the KPO trigger.
Also, the current execute_compelete method was unused in the KPO operator
and was problematic if someone using it in an extended class since
now the trigger can also emit an event even if the pod is in the pod intermediate state.
one reported issue: #37279 (comment)
In this PR I'm restoring the trigger event dict structure.
Also, deprecating the execute_complete method

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[vchiapaikeo]

Hi @pankajastro , I tested the same snippet that I tested here: #37279 (comment)

And this time it worked! 🎉

Thank you for the quick fix!

[pankajkoti]

Thank you so much @vchiapaikeo for quickly testing this out