Remove declaration of removed function

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: willmmiles

wled00/fcn_declare.h

@@ -176,7 +176,6 @@ void serializeSegment(const JsonObject& root, const Segment& seg, byte id, bool
 void serializeState(JsonObject root, bool forPreset = false, bool includeBri = true, bool segmentBounds = true, bool selectedSegmentsOnly = false);
 void serializeInfo(JsonObject root);
 void serializeModeNames(JsonArray arr);
-void serializeModeData(JsonArray fxdata);
 void serializePins(JsonObject root);
 void serveJson(AsyncWebServerRequest* request);
 #ifdef WLED_ENABLE_JSONLIVE