"post_init_hook" not working - Odoo 17

I'm trying to initialize the signature for base.user_root by creating a post_init_hook.

In the __init__.py file, I wrote the following code:

def update_odoo_bot_signature(env):
    user = env.ref('base.user_root')
    print(">>> Running post_init_hook to update OdooBot signature >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>")
    signature = '''
        <div style="font-family: Arial; font-size: 14px;">
            <p>Trân trọng,</p>
            <p><strong>Odoo Bot</strong></p>
            <p>Công ty TNHH ABC 12344444</p>
            <p><a href="https://yourcompany.com">https://yourcompany.com</a></p>
        </div>
    '''
    user.write({'signature': signature})


And in the __manifest__.py file, I configured it like this:

"post_init_hook": "update_odoo_bot_signature",



However, when I upgrade the module, the signature for the OdooBot record is not updated.