[IMP] hr_expense: Don't hide taxes on hr.expense when product has cost

Problem
---------
In 15, taxes are hidden from hr.expense when the expense category has a
cost. They can however be configured and added. The current behaviour is
counter intuitive.

Objective
---------
Don't hide taxes when product has cost in v15.

Solution
---------
Remove the `hidden` attribute in the expense xml form as well as the
`groups` attribute.

task-3491868

closes odoo/odoo#134147

Signed-off-by: Quentin De Paoli <qdp@odoo.com>

addons/hr_expense/views/hr_expense_views.xml

@@ -167,8 +167,8 @@
                                 <field name="total_amount_company" style="vertical-align: top;" widget='monetary' options="{'currency_field': 'company_currency_id'}"/>
                                 <field name="label_convert_rate"/>
                             </div>
-                            <field name="tax_ids" widget="many2many_tags" groups="account.group_account_readonly"
-                                attrs="{'readonly': [('is_editable', '=', False)], 'invisible': [('product_has_cost', '=', True)]}"
+                            <field name="tax_ids" widget="many2many_tags"
+                                attrs="{'readonly': [('is_editable', '=', False)]}"
                                 context="{'default_company_id': company_id, 'default_type_tax_use': 'purchase', 'default_price_include': 1}" placeholder="Included in price taxes" />
                         </group><group>
                             <field name="reference" groups="account.group_account_readonly" attrs="{'readonly': [('is_ref_editable', '=', False)], 'invisible': [('product_has_cost', '=', True)]}"/>