indicator: enlarge the LVGL heap for low-zoom map tiles

The heap was 3MB and the image cache reserves 1.5MB of it, so a low-zoom map
tile could not find a large enough contiguous block to decode and rendered
white. 5MB of the 8MB PSRAM fixes it with room to spare.

variants/esp32s3/seeed-sensecap-indicator/platformio.ini

@@ -84,7 +84,11 @@ build_flags =
   -D HAS_SCREEN=1
   -D HAS_TFT=1
   -D DISPLAY_SET_RESOLUTION
-  -D RAM_SIZE=3072
+  # LVGL heap (RAM_SIZE * 1024). The image cache reserves 1.5MB of it, and a
+  # low-zoom map tile needs a large contiguous realloc to decode that the
+  # remainder could not satisfy, so those tiles rendered white. 5MB of the
+  # 8MB PSRAM leaves comfortable headroom for the decode plus the cache.
+  -D RAM_SIZE=5120
   -D LV_LVGL_H_INCLUDE_SIMPLE
   -D LV_CONF_INCLUDE_SIMPLE
   -D LV_COMP_CONF_INCLUDE_SIMPLE