chore(deps): update quay.io/keycloak/keycloak docker tag to v26

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
quay.io/keycloak/keycloak	final	major	24.0.3 → 26.6.1
quay.io/keycloak/keycloak	stage	major	24.0.3 → 26.6.1

---

Configuration

📅 Schedule: (UTC)

• Branch creation
  • At any time (no schedule defined)
• Automerge
  • At any time (no schedule defined)

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about these updates again.

---

• If you want to rebase/retry this PR, check this box

---

This PR was generated by Mend Renovate. View the repository job log.