[#10966] Fix 500 when email is malformed

spec/controllers/email_checker_controller_spec.rb

@@ -45,5 +45,13 @@ describe EmailCheckerController, type: :controller do
         expect(body).to eq({ success: false })
       end
     end
+
+    context 'malformed' do
+      let(:params) { { email: { some: 'hash' } } }
+      it do
+        expect(response).to have_http_status(:success)
+        expect(body).to eq({ success: false })
+      end
+    end
   end
 end