[FIX] report_xlsx: keep sudo

[danielduqma]

Explicit sudo(False) is not needed anymore, as Odoo core also removed it from the other QWeb reports (see https://github.com/odoo/odoo/commit/ffc525419a71aeb05ede6b59dda9e62286a5e66e)

This change was made for 14.0 in https://github.com/OCA/reporting-engine/pull/587 (see related issue https://github.com/OCA/reporting-engine/issues/586). Odoo server was modified for 16.0 in https://github.com/odoo/odoo/commit/ffc525419a71aeb05ede6b59dda9e62286a5e66e removing all sudo(False) from other the other QWeb render processes, so here it is not needed anymore.