fix jest test issues

app/soapbox/features/auth_login/components/__tests__/__snapshots__/login_form-test.js.snap

@@ -2,7 +2,7 @@
 
 exports[`<LoginForm /> renders correctly 1`] = `
 <form
-  className="simple_form new_user"
+  className="simple_form new_user" method='post'
 >
   <fieldset>
     <div

app/soapbox/features/auth_login/components/__tests__/__snapshots__/login_page-test.js.snap

@@ -2,7 +2,7 @@
 
 exports[`<LoginPage /> renders correctly on load 1`] = `
 <form
-  className="simple_form new_user"
+  className="simple_form new_user" method='post'
   onSubmit={[Function]}
 >
   <fieldset

app/soapbox/features/forms/__tests__/__snapshots__/forms-test.js.snap

@@ -78,6 +78,7 @@ exports[`<SimpleForm /> renders correctly 1`] = `
 <form
   acceptCharset="UTF-8"
   className="simple_form"
+  method='post'
   onSubmit={[Function]}
 />
 `;