BUG/MINOR: quic: Missing STREAM frame type updated

This patch follows this commit which was not sufficient:
  BUG/MINOR: quic: Missing STREAM frame data pointer updates

Indeed, after updating the ->offset field, the bit which informs the
frame builder of its presence must be systematically set.

This bug was revealed by the following BUG_ON() from
quic_build_stream_frame() :
  bug condition "!!(frm->type & 0x04) != !!stream->offset.key" matched at src/quic_frame.c:515

This should fix the last crash occured on github issue #2074.

Must be backported to 2.6 and 2.7.
diff --git a/include/haproxy/quic_frame.h b/include/haproxy/quic_frame.h
index f75d7e6..cf489f7 100644
--- a/include/haproxy/quic_frame.h
+++ b/include/haproxy/quic_frame.h
@@ -255,11 +255,15 @@
 }
 
 /* Move forward <strm> STREAM frame by <data> bytes. */
-static inline void qc_stream_frm_mv_fwd(struct quic_stream *strm, uint64_t data)
+static inline void qc_stream_frm_mv_fwd(struct quic_frame *frm, uint64_t data)
 {
+	struct quic_stream *strm = &frm->stream;
 	struct buffer cf_buf;
 
+	/* Set offset bit if not already there. */
 	strm->offset.key += data;
+	frm->type |= QUIC_STREAM_FRAME_TYPE_OFF_BIT;
+
 	strm->len -= data;
 	cf_buf = b_make(b_orig(strm->buf),
 	                b_size(strm->buf),
diff --git a/src/quic_conn.c b/src/quic_conn.c
index f4a36f0..25ece80 100644
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -1905,7 +1905,7 @@
 			else if (strm_frm->offset.key < stream_desc->ack_offset) {
 				uint64_t diff = stream_desc->ack_offset - strm_frm->offset.key;
 
-				qc_stream_frm_mv_fwd(strm_frm, diff);
+				qc_stream_frm_mv_fwd(frm, diff);
 				TRACE_DEVEL("updated partially acked frame",
 				            QUIC_EV_CONN_PRSAFRM, qc, frm);
 			}
@@ -2562,7 +2562,7 @@
 			else if (strm_frm->offset.key < stream_desc->ack_offset) {
 				uint64_t diff = stream_desc->ack_offset - strm_frm->offset.key;
 
-				qc_stream_frm_mv_fwd(strm_frm, diff);
+				qc_stream_frm_mv_fwd(frm, diff);
 				TRACE_DEVEL("updated partially acked frame",
 				            QUIC_EV_CONN_PRSAFRM, qc, frm);
 			}
@@ -7301,7 +7301,7 @@
 				else if (strm->offset.key < stream_desc->ack_offset) {
 					uint64_t diff = stream_desc->ack_offset - strm->offset.key;
 
-					qc_stream_frm_mv_fwd(strm, diff);
+					qc_stream_frm_mv_fwd(cf, diff);
 					TRACE_DEVEL("updated partially acked frame",
 					            QUIC_EV_CONN_PRSAFRM, qc, cf);
 				}