[chaotic-good] Fix fuzzer found crash in server transport code (#36852)

Closes #36852

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/36852 from ctiller:f-st 5ffc88a71f
PiperOrigin-RevId: 641300922

src/core/ext/transport/chaotic_good/server/chaotic_good_server.cc

@@ -443,13 +443,10 @@ void ChaoticGoodServerListener::ActiveConnection::HandshakingState::
 
 Timestamp ChaoticGoodServerListener::ActiveConnection::HandshakingState::
     GetConnectionDeadline() {
-  if (connection_->args().Contains(GRPC_ARG_SERVER_HANDSHAKE_TIMEOUT_MS)) {
-    return Timestamp::Now() +
-           connection_->args()
-               .GetDurationFromIntMillis(GRPC_ARG_SERVER_HANDSHAKE_TIMEOUT_MS)
-               .value();
-  }
-  return Timestamp::Now() + kConnectionDeadline;
+  return Timestamp::Now() +
+         connection_->args()
+             .GetDurationFromIntMillis(GRPC_ARG_SERVER_HANDSHAKE_TIMEOUT_MS)
+             .value_or(kConnectionDeadline);
 }
 
 void ChaoticGoodServerListener::Orphan() {

test/core/end2end/fuzzers/server_fuzzer_chaotic_good_corpus/clusterfuzz-testcase-minimized-server_fuzzer_chaotic_good-5907858541051904

@@ -0,0 +1,14 @@
+network_input {
+  input_segments {
+    segments {
+      header {
+      }
+    }
+  }
+}
+channel_args {
+  args {
+    key: "grpc.server_handshake_timeout_ms"
+    str: "65537"
+  }
+}