fix(fs-repo-15-to-16): support existing listener

some users might've enabled listener while testing 0.29.0
and if it was on the same port, they could just forget to remove it,
because it was ignored.

in such case, the old code would add  /webrtc-direct and 'continue' loop
which woudl mean /quic-v1 is not added back, effectively breaking QUIC.

this adds fix + regression test for that scenario

fs-repo-15-to-16/migration/migration.go

@@ -186,26 +186,19 @@ func convert(in io.Reader, out io.Writer) error {
 			uniq := map[string]struct{}{}
 			for _, v := range swarm {
 				if addr, ok := v.(string); ok {
-
 					// if /quic-v1, add /webrtc-direct under the same port
 					if quicRegex.MatchString(addr) {
 						newAddr := quicRegex.ReplaceAllString(addr, "/webrtc-direct")
-
-						if _, ok := uniq[newAddr]; ok {
-							continue
+						if _, ok := uniq[newAddr]; !ok {
+							uniq[newAddr] = struct{}{}
+							newSwarm = append(newSwarm, newAddr)
 						}
-						uniq[newAddr] = struct{}{}
-
-						newSwarm = append(newSwarm, newAddr)
 					}
-
 					// keep original addr
-					if _, ok := uniq[addr]; ok {
-						continue
+					if _, ok := uniq[addr]; !ok {
+						uniq[addr] = struct{}{}
+						newSwarm = append(newSwarm, addr)
 					}
-					uniq[addr] = struct{}{}
-
-					newSwarm = append(newSwarm, addr)
 					continue
 				}
 				newSwarm = append(newSwarm, v)

fs-repo-15-to-16/test-e2e/repo-v15/config

@@ -12,6 +12,7 @@
     "NoAnnounce": [
       "/ip4/0.0.0.0/tcp/4001",
       "/ip6/::/tcp/4001",
+      "/ip4/0.0.0.0/udp/4001/webrtc-direct",
       "/ip4/0.0.0.0/udp/4001/quic-v1",
       "/ip4/0.0.0.0/udp/4001/quic-v1/webtransport",
       "/ip6/::/udp/4001/quic-v1",

fs-repo-15-to-16/test-e2e/repo-v16/config.15-to-16.bak

@@ -12,6 +12,7 @@
     "NoAnnounce": [
       "/ip4/0.0.0.0/tcp/4001",
       "/ip6/::/tcp/4001",
+      "/ip4/0.0.0.0/udp/4001/webrtc-direct",
       "/ip4/0.0.0.0/udp/4001/quic-v1",
       "/ip4/0.0.0.0/udp/4001/quic-v1/webtransport",
       "/ip6/::/udp/4001/quic-v1",