Avoid ugly exception in log on unknown inv type

It is unexpected behavior for `ToString` to raise an exception. It
is expected to do a best-effort attempt at formatting but never fail.

Catch the exception and simply print unknown inv types as hexadecimal.

Fixes #9110.

src/protocol.cpp

@@ -181,7 +181,11 @@ std::string CInv::GetCommand() const
 
 std::string CInv::ToString() const
 {
-    return strprintf("%s %s", GetCommand(), hash.ToString());
+    try {
+        return strprintf("%s %s", GetCommand(), hash.ToString());
+    } catch(const std::out_of_range &) {
+        return strprintf("0x%08x %s", type, hash.ToString());
+    }
 }
 
 const std::vector<std::string> &getAllNetMessageTypes()