fix(colorlcd): Missing R9M Flex power option menu (#1880)

* Update model_setup.cpp

Adds R9M Flex (ACCST, non ACCESS) Power option GUI menu item, which is currently missing.

* Update model_setup.cpp

* R9M Flex power option menu for colorlcd

Adds power selection menu for R9M Flex  (ACCST, pre 2019) on colorlcd radios. Tested working on a tx16s.
https://github.com/EdgeTX/edgetx/issues/1187

* Just test for FCC variants

Co-authored-by: Peter Feerick <peter.feerick@gmail.com>

radio/src/gui/colorlcd/model_setup.cpp

@@ -1251,7 +1251,7 @@ class ModuleWindow : public FormGroup {
 #endif
 
       // R9M Power
-      if (isModuleR9M_FCC(moduleIdx)) {
+      if (isModuleR9M_FCC_VARIANT(moduleIdx)) {
         new StaticText(this, grid.getLabelSlot(true), STR_RF_POWER, 0, COLOR_THEME_PRIMARY1);
         new Choice(this, grid.getFieldSlot(), STR_R9M_FCC_POWER_VALUES, 0, R9M_FCC_POWER_MAX,
                    GET_SET_DEFAULT(g_model.moduleData[moduleIdx].pxx.power));