Bangle.js2: Remove buzz when going back in a menu using the button (not the widget)

fix https://github.com/espruino/Espruino/issues/2670

ChangeLog

@@ -13,6 +13,7 @@
             STM32: Tidy up WAKEUP timer handling to ensure the Wakeup is always the first item in the queue
             E.defrag now defrags with interrupts enabled (also fix potential crash with 2 flat strings end to end)
             Swap to using locks for watch&timer arrays (uses 4b more RAM, but faster and no defrag issues)
+            Bangle.js2: Remove buzz when going back in a menu using the button (not the widget)
 
      2v28 : Add `E.internal` as a way to access the 'hidden root' containing Espruino internal variables that previously needed `global["\xff"]`
             Bangle.js: Fix back handler not removed when using E.setUI with a back button but without widgets (#2636)

libs/js/banglejs/Bangle_setUI_Q3.js

@@ -127,7 +127,7 @@
     if (Bangle.btnWatches===undefined)
       Bangle.btnWatches = [ setWatch(function() {
         Bangle.btnWatches = undefined; // watch doesn't repeat
-        b().then(() => options.back());
+        options.back();
       }, BTN1, {edge:"rising"}) ];
     // if we have widgets loaded *and* visible at the top, add a back widget (see #3788)
     if (global.WIDGETS && Bangle.appRect.y) {