Wizrad: add condition to useHostnameValidation in case of empty string

this adds condition to useHostnameValidation in case of empty string
if user decide to delete the value in hostname field

src/Components/CreateImageWizard/utilities/useValidation.tsx

@@ -188,15 +188,22 @@ export function useHostnameValidation(): StepValidation {
   const errorMessage =
     'Invalid hostname. The hostname should be composed of up to 64 7-bit ASCII lower-case alphanumeric characters or hyphens forming a valid DNS domain name. It is recommended that this name contains only a single label, i.e. without any dots.';
 
+  let hostnameError = '';
+  let disabledNext = false;
   if (!isHostnameValid(hostname)) {
-    return {
-      errors: {
-        hostname: errorMessage,
-      },
-      disabledNext: true,
-    };
+    hostnameError = errorMessage;
+    disabledNext = true;
+  } else if (!hostname) {
+    // Hack to keep the error message from flickering in create mode
+    hostnameError = 'default';
   }
-  return { errors: {}, disabledNext: false };
+
+  return {
+    errors: {
+      hostname: hostnameError,
+    },
+    disabledNext: disabledNext,
+  };
 }
 
 export function useKernelValidation(): StepValidation {