Fix test failure in QuicSpdyStreamTest.HeadersAccumulatorNullptr

The test currently fails as the reference to an internal bug (b/215142466) gets removed automatically when the code is exported to open source. This CL removes the reference to this bug number in EXPECT_QUIC_BUG() so the test passes.

PiperOrigin-RevId: 424189391

quic/core/http/quic_spdy_stream_test.cc

diff --git a/quic/core/http/quic_spdy_stream_test.cc b/quic/core/http/quic_spdy_stream_test.cc
index 6ac7fe0..1ed9f1e 100644
--- a/quic/core/http/quic_spdy_stream_test.cc
+++ b/quic/core/http/quic_spdy_stream_test.cc
@@ -3445,7 +3445,7 @@
   EXPECT_CALL(*connection_, CloseConnection(_, _, _));
   bool result = true;
   EXPECT_QUIC_BUG(result = QuicSpdyStreamPeer::OnHeadersFrameEnd(stream_),
-                  "b215142466_OnHeadersFrameEnd.: 1$");
+                  "OnHeadersFrameEnd");
   EXPECT_FALSE(result);
 }