[FIX] web: attach document fix click on firefox

As of saas-11.3 there is a "Attach document" widget that is meant to
more easily add attachment.

But on firefox the click event is coming from the button, where on other
browsers it was possibly from a child element.

So the code expecting the child element did not work on firefox.

opw-1920842
closes #29903

addons/web/static/src/js/widgets/attach_document.js

@@ -11,7 +11,7 @@ var _t = core._t;
 var AttachDocument = Widget.extend({
     template: 'AttachDocument',
     events: {
-        'click span.o_attach_document': '_onClickAttachDocument',
+        'click': '_onClickAttachDocument',
         'change input.o_input_file': '_onFileChanged',
     },
     /**
@@ -76,6 +76,9 @@ var AttachDocument = Widget.extend({
      * @param {Event} ev
      */
     _onClickAttachDocument: function (ev) {
+        if ($(ev.target).is('input.o_input_file')) {
+            return;
+        }
         var fieldNames = this.getParent().canBeSaved(this.state.id);
         if (fieldNames.length) {
             return this._notifyInvalidFields(fieldNames);