Added enter again on invoice modal.

client/src/pages/sign-in/sign-in.page.jsx

@@ -2,5 +2,16 @@ import React from "react";
 import SignIn from "../../components/sign-in-form/sign-in-form.component";
 
 export default () => {
-  return <SignIn />;
+  return (
+    <div
+      style={{
+        display: "flex",
+        justifyContent: "center",
+        alignItems: "middle",
+        padding: "4em",
+      }}
+    >
+      <SignIn />
+    </div>
+  );
 };