Remove HTTP client generic Loop parameter

I think we initially thought we might need different clients for different
parts of the system, each with a unique loop  (e.g. we thought telemetry might
need some isolation). But that never happened, so it's just needless now,
especially since the async connect uses the non-generic *Loop type directly.

Author: karlseguin

src/app.zig

@@ -55,7 +55,7 @@ pub const App = struct {
             .telemetry = undefined,
             .app_dir_path = app_dir_path,
             .notification = notification,
-            .http_client = try http.Client.init(allocator, .{
+            .http_client = try http.Client.init(allocator, loop, .{
                 .max_concurrent = 3,
                 .http_proxy = config.http_proxy,
                 .proxy_type = config.proxy_type,

src/browser/xhr/xhr.zig

@@ -458,7 +458,6 @@ pub const XMLHttpRequest = struct {
             &self.url.?.uri,
             self,
             onHttpRequestReady,
-            self.loop,
         );
     }
 
@@ -494,7 +493,7 @@ pub const XMLHttpRequest = struct {
             }
         }
 
-        try request.sendAsync(self.loop, self, .{});
+        try request.sendAsync(self, .{});
         self.request = request;
     }