[BUG] Delegate Pattern not fully supported with spring-cloud library

Description

In a project I can configure delegatePattern=true (with interfaceOnly=false) to get delegate interfaces and controllers generated.

If however I set library=spring-cloud no controller is generated.

openapi-generator version

5.4.0, maven plugin.

OpenAPI declaration file content or url

This behaviour is obvious from the code in modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/SpringCodegen.java from line 480:

if (SPRING_CLOUD_LIBRARY.equals(library)) {
    supportingFiles.add(new SupportingFile("apiKeyRequestInterceptor.mustache",
            (sourceFolder + File.separator + configPackage).replace(".", java.io.File.separator),
            "ApiKeyRequestInterceptor.java"));
    supportingFiles.add(new SupportingFile("clientConfiguration.mustache",
            (sourceFolder + File.separator + configPackage).replace(".", java.io.File.separator),
            "ClientConfiguration.java"));
    apiTemplateFiles.put("apiClient.mustache", "Client.java");
    if (!additionalProperties.containsKey(SINGLE_CONTENT_TYPES)) {
        additionalProperties.put(SINGLE_CONTENT_TYPES, "true");
        this.setSingleContentTypes(true);
    }
} else {
    apiTemplateFiles.put("apiController.mustache", "Controller.java");
    supportingFiles.add(new SupportingFile("application.mustache",
            ("src.main.resources").replace(".", java.io.File.separator), "application.properties"));
    supportingFiles.add(new SupportingFile("homeController.mustache",
            (sourceFolder + File.separator + configPackage).replace(".", java.io.File.separator),
            "HomeController.java"));
    supportingFiles.add(new SupportingFile("openapi.mustache",
            ("src/main/resources").replace("/", java.io.File.separator), "openapi.yaml"));
    if (!reactive && !apiFirst){ 
        if (DocumentationProvider.SPRINGDOC.equals(getDocumentationProvider())){
            supportingFiles.add(new SupportingFile("springdocDocumentationConfig.mustache",
                (sourceFolder + File.separator + configPackage).replace(".", java.io.File.separator),
                "SpringDocConfiguration.java"));
        } else if (DocumentationProvider.SPRINGFOX.equals(getDocumentationProvider())) {
            supportingFiles.add(new SupportingFile("openapiDocumentationConfig.mustache",
                (sourceFolder + File.separator + configPackage).replace(".", java.io.File.separator),
                "SpringFoxConfiguration.java"));
        }
    }
}

There may be good reasons why both options are not compatible or actually should lead to different behaviour. However this is not clear from the documentation. Why noone should be able to use the delegate pattern together with Feign client generation seems not plausible to me.

Start in modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/SpringCodegen.java around line 480, and compare the spring-cloud branch with the controller-generating branch. Trace the apiClient.mustache and apiController.mustache selections, then determine and document the expected result when delegatePattern=true and library=spring-cloud. Done means the compatibility behavior is explicit and the generated output matches that decision.