fix compilation for esp32_4MB_M_debug

Add flag to save flash for debug messages

Author: softhack007

platformio.ini

@@ -1400,6 +1400,7 @@ build_unflags = ${common.build_unflags}
 build_flags = ${esp32_4MB_M_base.build_flags} 
   -D WLED_DISABLE_PARTICLESYSTEM1D ;; exceeds flash size limit
   -D WLED_DISABLE_PARTICLESYSTEM2D ;; exceeds flash size limit
+  -D WLEDMM_SAVE_FLASH             ;; save some flash, to have space for debug messages
   ${Debug_Flags.build_flags}
   -D CORE_DEBUG_LEVEL=2   ;; 2=warning
   -D WLED_RELEASE_NAME=esp32_4MB_M_debug