refactor: use _getContactsChannelsFS() instead of ifdefs

examples/companion_radio/DataStore.h

@@ -48,4 +48,7 @@ public:
   bool removeFile(FILESYSTEM* fs, const char* filename);
   uint32_t getStorageUsedKb() const;
   uint32_t getStorageTotalKb() const;
+
+private:
+  FILESYSTEM* _getContactsChannelsFS() const { if (_fsExtra) return _fsExtra; return _fs;};
 };