Address review comment to remove reundant if block

xds/src/main/java/io/grpc/xds/internal/security/certprovider/CertProviderSslContextProvider.java

@@ -82,9 +82,7 @@ protected CertProviderSslContextProvider(
     } else {
       certHandle = null;
     }
-    if (createRootCertInstance && sharedCertInstance) {
-      rootCertHandle = () -> { };
-    } else if (createRootCertInstance && !sharedCertInstance) {
+    if (createRootCertInstance && !sharedCertInstance) {
       CertificateProviderInfo certProviderInstanceConfig =
           getCertProviderConfig(certProviders, rootCertInstance.getInstanceName());
       rootCertHandle = certProviderInstanceConfig == null ? null