Update quay.io/keycloak/keycloak Docker tag to v26.4.1

This MR contains the following updates:

Package	Type	Update	Change
quay.io/keycloak/keycloak	service-image	minor	26.3.5 -> 26.4.1
quay.io/keycloak/keycloak		minor	26.3.5 -> 26.4.1

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