Starting freq fixes when no App Settings, and support for App Settings in Scanner App (Mode/BW/Step only) (#1153)

* Fix initial freq when no App Settings tpms
* Default POCSAG freq when no App Settings
* Enable Scanner App Settings for Modulation/BW/Step
* Default SONDE freq when no App Settings

firmware/application/apps/ui_scanner.hpp

@@ -95,6 +95,9 @@ class ScannerView : public View {
     // void set_parent_rect(const Rect new_parent_rect) override;
 
    private:
+    app_settings::SettingsManager settings_{
+        "scanner", app_settings::Mode::RX};
+
     NavigationView& nav_;
     RxRadioState radio_state_{};