Catch UnknownHostExceptions in legacy ping passthrough pings (#4331)

* Catch unknownhostexception to avoid network errors when using legacy ping passthrough

* Catch UnknownHostException separately, log a warning but no stacktrace

core/src/main/java/org/geysermc/geyser/ping/GeyserLegacyPingPassthrough.java

@@ -139,6 +139,9 @@ public class GeyserLegacyPingPassthrough implements IGeyserPingPassthrough, Runn
             this.geyser.getLogger().debug("Connection timeout for ping passthrough.");
         } catch (JsonParseException | JsonMappingException ex) {
             this.geyser.getLogger().error("Failed to parse json when pinging server!", ex);
+        } catch (UnknownHostException ex) {
+            // Don't reset pingInfo, as we want to keep the last known value
+            this.geyser.getLogger().warning("Unable to resolve remote host! Is the remote server down or invalid?");
         } catch (IOException e) {
             this.geyser.getLogger().error("IO error while trying to use legacy ping passthrough", e);
         }