Fix DEV UI startup when OIDC Dev UI is disabled

(cherry picked from commit 491dc36)

extensions/oidc/runtime/src/main/java/io/quarkus/oidc/runtime/devui/OidcDevJsonRpcService.java

@@ -45,7 +45,15 @@ public OidcDevJsonRpcService(HttpConfiguration httpConfiguration, SmallRyeConfig
         // we must always produce it when in DEV mode because we can't check for 'KeycloakDevServicesConfigBuildItem'
         // due to circular reference: JSON RPC provider is additional bean and 'LoggingSetupBuildItem' used by
         // 'KeycloakDevServicesProcessor' is created with combined index
-        OidcDevUiRpcSvcPropertiesBean props = Arc.container().instance(OidcDevUiRpcSvcPropertiesBean.class).get();
+        final var propsInstanceHandle = Arc.container().instance(OidcDevUiRpcSvcPropertiesBean.class);
+        final OidcDevUiRpcSvcPropertiesBean props;
+        if (propsInstanceHandle.isAvailable()) {
+            props = propsInstanceHandle.get();
+        } else {
+            // OIDC Dev UI is disabled, but this RPC service still gets initialized by Quarkus DEV UI
+            props = new OidcDevUiRpcSvcPropertiesBean(null, null, null, null, Map.of(), Map.of(), null, null, null, false, null,
+                    List.of(), false, false, null, null, false);
+        }
 
         this.httpPort = httpConfiguration.port;
         this.config = config;