Bangle.setUI: fix back btn not drawn in leftmost position

The bug seems to have snuck in when the back widget was no longer set
with Object.assign in commit 453def8 .

Author: thyttan

ChangeLog

@@ -30,6 +30,7 @@
             ESP32: Remove FlashFS, adjust partitions to increase available Storage from 256kB to 896kB
             Storage: Don't attempt to compact if it's obvious that we don't have space for the file even when compacted
             Increase Packet timeout from 1 to 5 sec (increase reliability over slow Bluetooth LE connections)
+            Bangle.js: fix .setUI back button stopped being drawn in the leftmost position after recent changes.
 
      2v25 : ESP32C3: Get analogRead working correctly
             Graphics: Adjust image alignment when rotating images to avoid cropping (fix #2535)

libs/js/banglejs/Bangle_setUI_F18.js

@@ -110,7 +110,7 @@
       };
       Bangle.prependListener("touch", touchHandler);
       // add widget - 'remove' function will remove the widgets
-      WIDGETS.back = {
+      WIDGETS = Object.assign({back:{
         area:"tl", width:24,
         draw:e=>g.reset().setColor("#f00").drawImage(atob("GBiBAAAYAAH/gAf/4A//8B//+D///D///H/P/n+H/n8P/n4f/vwAP/wAP34f/n8P/n+H/n/P/j///D///B//+A//8Af/4AH/gAAYAA=="),e.x,e.y),
         remove:function(noclear){
@@ -122,7 +122,7 @@
           delete WIDGETS.back;
           if (!noclear) Bangle.drawWidgets();
         }
-      };
+      }},global.WIDGETS)
       if (!hadBackWidget) Bangle.drawWidgets();
     }
   }

libs/js/banglejs/Bangle_setUI_F18.min.js

@@ -137,7 +137,7 @@
       };
       Bangle.prependListener("touch", touchHandler);
       // add widget - 'remove' function will remove the widgets
-      WIDGETS.back = {
+      WIDGETS = Object.assign({back:{
         area:"tl", width:24,
         draw:e=>g.reset().setColor("#f00").drawImage(atob("GBiBAAAYAAH/gAf/4A//8B//+D///D///H/P/n+H/n8P/n4f/vwAP/wAP34f/n8P/n+H/n/P/j///D///B//+A//8Af/4AH/gAAYAA=="),e.x,e.y),
         remove:function(noclear){
@@ -149,7 +149,7 @@
           delete WIDGETS.back;
           if (!noclear) Bangle.drawWidgets();
         }
-      };
+      }},global.WIDGETS)
       if (!hadBackWidget) Bangle.drawWidgets();
     }
   }