Tweak wait_until option

Small tweaks to https://github.com/lightpanda-io/browser/pull/1896

Improve the wait ergonomics with an Option with default parameter. Revert
page pointer logic to original (don't think that change was necessary).

src/cdp/domains/lp.zig

@@ -280,7 +280,7 @@ test "cdp.lp: action tools" {
     const page = try bc.session.createPage();
     const url = "http://localhost:9582/src/browser/tests/mcp_actions.html";
     try page.navigate(url, .{ .reason = .address_bar, .kind = .{ .push = null } });
-    _ = bc.session.wait(5000, .load);
+    _ = bc.session.wait(.{});
 
     // Test Click
     const btn = page.document.getElementById("btn", page).?.asNode();