Improved the event which is thrown in the event log tab

[Nataneljpwd]

…iles for k8s exec

---

After a lot of debugging, I found that adding the pod termination reason to k8s executor event log will aid a lot in understanding underlying issues in the cluster and termination errors.
In example, when a pod gets evicted or oom killed, it will now show up in the event tab.

Was generative AI tooling used to co-author this PR?

• Yes (please specify the tool below)
• No

---

• Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
• For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
• When adding dependency, check compliance with the ASF 3rd Party License Policy.
• For significant user-facing changes create newsfragment: {pr_number}.significant.rst or {issue_number}.significant.rst, in airflow-core/newsfragments.