fix: default invite user modal global role to least-privilege

Pre-select "Internal User Viewer" in the Global Proxy Role dropdown
on both the standalone and embedded Invite User forms so admins don't
have to remember to pick a role, and the default lands on the least
privileged option rather than silently posting an undefined role.

ui/litellm-dashboard/src/components/CreateUserButton.tsx

@@ -175,7 +175,14 @@ export const CreateUserButton: React.FC<CreateuserProps> = ({
   // Modify the return statement to handle embedded mode
   if (isEmbedded) {
     return (
-      <Form form={form} onFinish={handleCreate} labelCol={{ span: 8 }} wrapperCol={{ span: 16 }} labelAlign="left">
+      <Form
+        form={form}
+        onFinish={handleCreate}
+        labelCol={{ span: 8 }}
+        wrapperCol={{ span: 16 }}
+        labelAlign="left"
+        initialValues={{ user_role: "internal_user_viewer" }}
+      >
         <Alert
           message="Email invitations"
           description={
@@ -257,7 +264,14 @@ export const CreateUserButton: React.FC<CreateuserProps> = ({
             className="mb-4"
           />
         </Space>
-        <Form form={form} onFinish={handleCreate} labelCol={{ span: 8 }} wrapperCol={{ span: 16 }} labelAlign="left">
+        <Form
+          form={form}
+          onFinish={handleCreate}
+          labelCol={{ span: 8 }}
+          wrapperCol={{ span: 16 }}
+          labelAlign="left"
+          initialValues={{ user_role: "internal_user_viewer" }}
+        >
           <Form.Item label="User Email" name="user_email">
             <Input />
           </Form.Item>