Update to latest mixing module

This includes a fix for a potential deadlock when reconnecting to dcrd in RPC
sync mode, and to refuse KEs that are received too early before the epoch.

go.mod

@@ -21,7 +21,7 @@ require (
 	github.com/decred/dcrd/dcrutil/v4 v4.0.2
 	github.com/decred/dcrd/gcs/v4 v4.1.0
 	github.com/decred/dcrd/hdkeychain/v3 v3.1.2
-	github.com/decred/dcrd/mixing v0.4.0
+	github.com/decred/dcrd/mixing v0.4.1-0.20240708173353-9731e3bdd493
 	github.com/decred/dcrd/rpc/jsonrpc/types/v4 v4.3.0
 	github.com/decred/dcrd/rpcclient/v8 v8.0.1
 	github.com/decred/dcrd/txscript/v4 v4.1.1

go.sum

@@ -63,8 +63,8 @@ github.com/decred/dcrd/gcs/v4 v4.1.0 h1:tpW7JW53yJZlgNwl/n2NL1b8NxHaIPRUyNuLMkB/
 github.com/decred/dcrd/gcs/v4 v4.1.0/go.mod h1:nPTbGM/I3Ihe5KFvUmxZEqQP/jDZQjQ63+WEi/f4lqU=
 github.com/decred/dcrd/hdkeychain/v3 v3.1.2 h1:x25WuuE7zM/20EynuVMyOhL0K8BwGBBsexGq8xTiHFA=
 github.com/decred/dcrd/hdkeychain/v3 v3.1.2/go.mod h1:FnNJmZ7jqUDeAo6/c/xkQi5cuxh3EWtJeMmW6/Z8lcc=
-github.com/decred/dcrd/mixing v0.4.0 h1:XblHAND4Vt5owVUvjPorDg30eWT53DpCZs6VF7U1t6U=
-github.com/decred/dcrd/mixing v0.4.0/go.mod h1:ySvVwTZyVz5YvevA6YjPrB6pJEwTm7IkHohTfaiHh2c=
+github.com/decred/dcrd/mixing v0.4.1-0.20240708173353-9731e3bdd493 h1:BUcTW5HF8QrPf1ubDx6HxITV+SBhLwv99NhHwRXKhy4=
+github.com/decred/dcrd/mixing v0.4.1-0.20240708173353-9731e3bdd493/go.mod h1:ySvVwTZyVz5YvevA6YjPrB6pJEwTm7IkHohTfaiHh2c=
 github.com/decred/dcrd/rpc/jsonrpc/types/v4 v4.3.0 h1:l0DnCcILTNrpy8APF3FLN312ChpkQaAuW30aC/RgBaw=
 github.com/decred/dcrd/rpc/jsonrpc/types/v4 v4.3.0/go.mod h1:j+kkRPXPJB5S9VFOsx8SQLcU7PTFkPKRc1aCHN4ENzA=
 github.com/decred/dcrd/rpcclient/v8 v8.0.1 h1:hd81e4w1KSqvPcozJlnz6XJfWKDNuahgooH/N5E8vOU=