Update to the latest package:sse

Change-Id: I8f2f25a72f459fbea4fdd9bf4e81a7d6f5704a50
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/183182
Commit-Queue: Nate Bosch <nbosch@google.com>
Auto-Submit: Nate Bosch <nbosch@google.com>
Reviewed-by: Gary Roumanis <grouma@google.com>

DEPS

@@ -147,7 +147,7 @@ vars = {
   "source_maps-0.9.4_rev": "38524",
   "source_maps_rev": "53eb92ccfe6e64924054f83038a534b959b12b3e",
   "source_span_rev": "aecb614eac3caa333658493b31a32b4e904cb0a4",
-  "sse_tag": "9a486d058a17e880afa9cc1c3c0dd8bad726bcbc",
+  "sse_tag": "e93a783755b9b048b9156f795461d17a5ece9ce8",
   "stack_trace_tag": "6788afc61875079b71b3d1c3e65aeaa6a25cbc2f",
   "stagehand_rev": "e64ac90cac508981011299c4ceb819149e71f1bd",
   "stream_channel_tag": "d7251e61253ec389ee6e045ee1042311bced8f1d",

pkg/dds/pubspec.yaml

@@ -18,7 +18,7 @@ dependencies:
   shelf: ^0.7.5
   shelf_proxy: ^0.1.0+7
   shelf_web_socket: ^0.2.3
-  sse: ^3.5.0
+  sse: ^3.7.0
   stream_channel: ^2.0.0
   vm_service: ^6.0.1-nullsafety.0
   web_socket_channel: ^1.1.0

pkg/dds/test/web/sse_smoke_driver.dart

@@ -24,9 +24,6 @@ Future<void> main() async {
   final ddsUri = await testerStream.next;
   final ddsChannel = SseClient(ddsUri);
 
-  // Wait for ddsChannel to be established.
-  await ddsChannel.onOpen.first;
-
   final vmService = VmService(
     ddsChannel.stream,
     (e) => ddsChannel.sink.add(e),