fix: strings constness (#84)

radio/src/thirdparty/libopenui/src/bitmapbuffer.h

@@ -338,7 +338,7 @@ class BitmapBuffer: public BitmapBufferBase<pixel_t>
       return drawSizedText(x, y, s, strlen(s), flags);
     }
 
-    coord_t drawTextAtIndex(coord_t x, coord_t y, const char** s, uint8_t idx, LcdFlags flags = 0)
+    coord_t drawTextAtIndex(coord_t x, coord_t y, const char *const *s, uint8_t idx, LcdFlags flags = 0)
     {
       return drawText(x, y, s[idx], flags);
     }

radio/src/thirdparty/libopenui/src/libopenui_helpers.h

@@ -79,7 +79,7 @@ inline T sgn(T a)
 }
 
 // TODO duplicated code
-inline std::string TEXT_AT_INDEX(const char** val, uint8_t idx)
+inline std::string TEXT_AT_INDEX(const char *const *val, uint8_t idx)
 {
   return std::string(val[idx]);
 }