Android: GB Activity tracks, handle first read

... when there is no id of the last read recorder log supplied from
Gadgetbridge.

apps/android/boot.js

@@ -201,8 +201,10 @@
 
       "listRecs": function() { // GB({t:"listRecs", id:"20230616a"})
         let recs = require("Storage").list(/^recorder\.log.*\.csv$/,{sf:true}).map(s => s.slice(12, 21));
+        if (event.id.length > 2) { // Handle if there was no id supplied. Then we send a list all available recorder logs back.
         recs = recs.slice(recs.indexOf(event.id)); // FIXME: Currently does not handle if the last fetched log was deleted on the watch, so that there won't be any entry corresponding to `event.id`
         recs.shift();
+        }
         Bluetooth.println("");
         Bluetooth.println(JSON.stringify({t:"trksList", list: recs})); // TODO: split up in multiple transmissions?
       },