pw_bluetooth: Avdtp emboss fix StreamEndPointDiscoveryResponse

Bug: 381291639
Change-Id: Ife9d0547848175369767e398c391867de48495ad
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/254114
Docs-Not-Needed: Charlie Boutier <charliebout@google.com>
Reviewed-by: Ben Lawson <benlawson@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Commit-Queue: Charlie Boutier <charliebout@google.com>

pw_bluetooth/public/pw_bluetooth/avdtp.emb

@@ -201,11 +201,12 @@ struct StreamEndPointDiscoveryCommand:
   0 [+2]  SignalingHeader  signaling_header
 
 
-struct StreamEndPointDiscoveryResponse:
+struct StreamEndPointDiscoveryResponse(length: UInt:32):
   -- Cf. 8.6.2 AVDTP_DISCOVER_RSP
   [requires: signaling_header.message_type == MessageType.RESPONSE_ACCEPT && signaling_header.signal_identifier == SignalIdentifierCode.AVDTP_DISCOVER]
-  0 [+2]  SignalingHeader  signaling_header
-  1 [+2]  Sep              acp_sep
+  let seps_size = length-SignalingHeader.$size_in_bytes
+  0     [+2]          SignalingHeader  signaling_header
+  $next [+seps_size]  Sep[]            others_acp_sep
 
 
 struct StreamEndPointDiscoveryReject: