[FIX] account: check if tax name on copy method

With this commit, it will check if the tax name is given by external method and take that name if any.

For example,
vals = {'rate': 5.2, 'name': 'Odoo New Tax'}
tax_template = self.env['account.tax'].search(domain, limit=1)
new_tax = tax_template.copy(default=vals)

Current Behavior:
new_tax.name => 'Odoo New Tax (Copy)'

Instead of 'Odoo New tax'

closes odoo/odoo#74722

Signed-off-by: oco-odoo <oco-odoo@users.noreply.github.com>