[FIX] web: JournalDashboardGraph widget crash Mk.II

Hardening of commit:995610c065bf0242cb5023cfad2940234395739e

The JournalDashboardGraph requires nv, which is lazyloaded.
However it requires nvd3.js which is loaded after nv.d3.js.
A function called in destroy is defined by nv.d3.js,
which can make the crashhappen with the right (wrong) timing.

opw 1873749

addons/web/static/src/js/fields/basic_fields.js

@@ -2055,7 +2055,7 @@ var JournalDashboardGraph = AbstractField.extend({
         return this._super.apply(this, arguments);
     },
     destroy: function () {
-        if ('nv' in window) {
+        if ('nv' in window && nv.utils && nv.utils.offWindowResize) {
             // if the widget is destroyed before the lazy loaded libs (nv) are
             // actually loaded (i.e. after the widget has actually started),
             // nv is undefined, but the handler isn't bound yet anyway