feat: register Keycloak JacksonProvider to prevent failing on unknown properties

[sergioa]

What this PR does / why we need it:

Keycloak client version requires updating unless we silently ignore unknown properties.

jakarta.ws.rs.client.ResponseProcessingException: jakarta.ws.rs.ProcessingException: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "verifiableCredentialsEnabled" (class org.keycloak.representations.idm.RealmRepresentation), not marked as ignorable (144 known properties: "userFederationMappers", "rememberMe", "duplicateEmailsAllowed", "adminEventsDetailsEnabled", "users", "clientOfflineSessionMaxLifespan", "webAuthnPolicyRequireResidentKey", "webAuthnPolicyPasswordlessAvoidSameAuthenticatorRegister", "components", "otpPolicyType", "accessCodeLifespanUserAction", "id", "webAuthnPolicyAttestationConveyancePreference", "enabledEventTypes", "applications", "webAuthnPolicyPasswordlessSignatureAlgorithms", "eventsListeners", "ssoSessionMaxLifespanRememberMe", "defaultDefaultClientScopes", "webAuthnPolicyPasswordlessCreateTimeout", "clientOfflineSessionIdleTimeout", "notBefore", "publicKey", "smtpServer", "clientPolicies", "resetPasswordAllowed", "webAuthnPolicyAvoidSameAuthenticatorRegister", "accessTokenLifespanForImplicitFlow", "webAuthnPolicyPasswordlessUserVerificationRequirement", "clientScopes", "internationalizationEnabled", "defaultRole", "accessTokenLifespan", "passwordCredentialGrantAllowed", "federatedUsers", "applicationScopeMappings" [truncated]])
 at [Source: REDACTED (`StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION` disabled); line: 1, column: 5296] (through reference chain: org.keycloak.representations.idm.RealmRepresentation["verifiableCredentialsEnabled"])

Which issue this PR fixes: fixes #1253

Special notes for your reviewer:

PR Readiness Checklist:

Complete these before marking the PR as ready to review:

• the CHANGELOG.md release notes have been updated to reflect any significant (and particularly user-facing) changes introduced by this PR

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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