Update quay.io/keycloak/keycloak Docker tag to v26.4.2

This MR contains the following updates:

Package	Type	Update	Change
quay.io/keycloak/keycloak	ironbank-docker	patch	26.4.1 -> 26.4.2
quay.io/keycloak/keycloak	stage	patch	26.4.1 -> 26.4.2

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