e2e: add test for case where an empty secret is populated later

[akshaysngupta]

Checklist

• The title of the PR is clear and informative
• If applicable, the changes made in the PR have proper test coverage
• Issues addressed by the PR are mentioned in the description followed by Fixes.

Description

This PR adds an E2E for a case where an empty secret is created without certificate information and is later populated with cert and key.
This simulates a case similar to Let's Encrypt where cert maybe empty in the beginning.

apiVersion: v1
kind: Secret
metadata:
  name: testsecret-tls
type: kubernetes.io/tls
data:
  tls.crt: ""
  tls.key: ""

Related to: #1070

Fixes