APIML not respecting zowe.verifyCertificates: DISABLED

Describe the bug

When zowe.verifyCertificates is set to DISABLED in zowe.yaml, several internal APIML components continue to enforce SSL certificate validation. The Gateway rejects outbound connections to services with untrusted/self-signed certificates, and the ZAAS client SDK always performs strict certificate validation, even when the user has explicitly disabled verification.

The root cause is two independent code paths that build their own SSL contexts without checking the verifySslCertificatesOfServices flag:

1. ConnectionUtil.getSslContext() (ConnectionUtil.java) — Builds the Netty SslContext used by Spring Cloud Gateway's reactive WebClient for all proxied traffic. It always loads the truststore into a real TrustManagerFactory regardless of the verifySslCertificatesOfServices value. Only hostname verification is conditionally disabled, not certificate trust validation. This affects the gatewayHttpClientFactory, webClient, and webClientClientCert beans in WebClientConfig.java.

2. ZaasHttpsClientProvider (ZaasHttpsClientProvider.java) — Creates its own SSLContext entirely independently of HttpsFactory. It always initializes a TrustManagerFactory with the truststore. Additionally, the ConfigProperties class for the ZAAS client doesn't even have a verifySslCertificatesOfServices field — only nonStrictVerifySslCertificatesOfServices exists — so there is no way to propagate the DISABLED setting.

Note: The Apache HttpClient path (HttpsFactory.getSslContext() in common-service-core) and the secureSslContext Spring bean (exposed by HttpConfig) do correctly handle DISABLED by returning a trust-all SSLContext. Components that consume that bean (e.g., RefreshablePeerEurekaNodes, DiscoveryRestTemplateConfig) work correctly.

Summary of which components respect the setting:

Steps to Reproduce

1. Set zowe.verifyCertificates: DISABLED in zowe.yaml
2. Configure a backend service with a self-signed certificate that is NOT in the APIML truststore
3. Register that service with the Discovery Service
4. Access the service through the API Gateway
5. Observe the Gateway returns 502/503 due to SSL handshake failure

Expected behavior

When zowe.verifyCertificates is set to DISABLED, all APIML components should skip certificate validation entirely — matching the behavior of other Zowe components. The Gateway should successfully proxy traffic to services regardless of their certificate status. The ZAAS client should connect without certificate errors.

Screenshots

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