odoo16/addons/sale_project/views/project_sharing_views.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>

    <record id="project_sharing_inherit_project_task_view_form" model="ir.ui.view">
        <field name="name">project.task.view.inherit</field>
        <field name="model">project.task</field>
        <field name="inherit_id" ref="project.project_sharing_project_task_view_form"/>
        <field name="arch" type="xml">
            <div name="button_box" position="inside">
                <field name="display_sale_order_button" invisible="1"/>
                <button class="oe_stat_button"
                        type="object" name="action_project_sharing_view_so" icon="fa-dollar"
                        attrs="{'invisible': [('display_sale_order_button', '=', False)]}"
                        string="Sales Order"/>
            </div>
            <xpath expr="//field[@name='partner_id']" position="attributes">
                <attribute name="options">{'no_open': True, 'no_create': True, 'no_edit': True}</attribute>
                <attribute name="context">{'res_partner_search_mode': 'customer'}</attribute>
            </xpath>
            <xpath expr="//field[@name='partner_id']" position="after">
                <field name="commercial_partner_id" invisible="1" />
                <field name="sale_line_id" string="Sales Order Item" attrs="{'invisible': [('partner_id', '=', False)]}" options='{"no_open": True}' readonly="1" context="{'create': False, 'edit': False, 'delete': False}"/>
            </xpath>
        </field>
    </record>

    <record id="project_sharing_inherit_project_task_view_search" model="ir.ui.view">
        <field name="name">project.task.search.inherit</field>
        <field name="model">project.task</field>
        <field name="inherit_id" ref="project.project_sharing_project_task_view_search"/>
        <field name="arch" type="xml">
            <xpath expr="//field[@name='partner_id']" position="after">
                <field name="sale_order_id" string="Sale Order" filter_domain="['|', ('sale_order_id', 'ilike', self), ('sale_line_id', 'ilike', self)]"/>
            </xpath>
            <xpath expr="//group/filter[@name='customer']" position="after">
                <filter name="sale_order_id" string="Sales Order Id" context="{'group_by': 'sale_order_id'}" />
            </xpath>
        </field>
    </record>

</odoo>