Missing fonts during build flatsphere.

[spairo1741]

• Working with IDF v5.5.5 and Eclipse.
• Errors regarding missing fonts of various sizes occur during the compilation of flatsphere v1.1.
• I select these fonts in the LVGL section of sdkconfig, but they are missing again after the build
  (checked sdkconfig.json in the /build directory).
  Example error:
  D:/esp32/workspace/flatsphere/main/ui/screens/ui_SetTime.c:63:49: error: 'lv_font_montserrat_30' undeclared (first use in this
  function); did you mean 'lv_font_montserrat_14'?
  63 | lv_obj_set_style_text_font(ui_RollerHours, &lv_font_montserrat_30, LV_PART_MAIN | LV_STATE_DEFAULT);
• Font sizes: 20, 30, 38, 40.