[FIX] account: edit tax on draft invoice only

Before this commit, Edit pencil on the widget `tax-group-custom-field` was visible on canceled Invoice as well.

Now, Edit pencil will be visible on Draft invoices only.

closes odoo/odoo#53680

X-original-commit: c5a02d3587c33fcf1bd6a0c78f97772a95652801
Signed-off-by: Quentin De Paoli (qdp) <qdp@openerp.com>

addons/account/static/src/js/tax_group.js

@@ -91,7 +91,7 @@ odoo.define('account.tax_group', function (require) {
             // Display the pencil and allow the event to click and edit only on purchase that are not posted and in edit mode.
             // since the field is readonly its mode will always be readonly. Therefore we have to use a trick by checking the 
             // formRenderer (the parent) and check if it is in edit in order to know the correct mode.
-            var displayEditWidget = self._isPurchaseDocument() && this.record.data.state !== 'posted' && this.getParent().mode === 'edit';
+            var displayEditWidget = self._isPurchaseDocument() && this.record.data.state === 'draft' && this.getParent().mode === 'edit';
             this.$el.html($(QWeb.render('AccountTaxGroupTemplate', {
                 lines: self.value,
                 displayEditWidget: displayEditWidget,