Correctly initialise WebPush connection (#2417)

The `ipaddr` arg here is being interpreted as a positional arg (since
the keyword arg doesn't exist), which results in an invalid connection
object. This was causing push notifications to silently fail.

We should initialise the property on the object instead.

test/lib/web_push/persistent_request_test.rb

@@ -0,0 +1,26 @@
+require "test_helper"
+
+class WebPush::PersistentRequestTest < ActiveSupport::TestCase
+  PUBLIC_TEST_IP = "142.250.185.206"
+  ENDPOINT = "https://fcm.googleapis.com/fcm/send/test123"
+
+  test "pins connection to endpoint_ip" do
+    request = stub_request(:post, ENDPOINT)
+      .with(ipaddr: PUBLIC_TEST_IP)
+      .to_return(status: 201)
+
+    notification = WebPush::Notification.new(
+      title: "Test",
+      body: "Test notification",
+      path: "/test",
+      badge: 0,
+      endpoint: ENDPOINT,
+      endpoint_ip: PUBLIC_TEST_IP,
+      p256dh_key: "BNcRdreALRFXTkOOUHK1EtK2wtaz5Ry4YfYCA_0QTpQtUbVlUls0VJXg7A8u-Ts1XbjhazAkj7I99e8QcYP7DkM",
+      auth_key: "tBHItJI5svbpez7KI4CCXg"
+    )
+    notification.deliver
+
+    assert_requested request
+  end
+end