Fix error where GRAINS button did not work

code/daisy-looper/ui.h

@@ -465,7 +465,7 @@ class Ui {
         });
 
         // Select the active Effect (FILTER)
-        button_5.onPress([this, n](){ 
+        button_6.onPress([this, n](){ 
           fx_mode = FX_MODE_FILTER;
           pot_5.setDisplayMode("Lowpass", 100.0f, POT_DISPLAY_MODE_PERCENT);
           pot_6.setDisplayMode("Highpass", 100.0f, POT_DISPLAY_MODE_PERCENT);