Fresh site: Drop erp5_core_proxy_field_legacy requirement
Drop requirement of erp5_core_proxy_field_legacy on clean and fresh site.
Also partially revert 501c443d, which added this BT5 in tests, while it is not supposed to be needed anymore.
Drop requirement of erp5_core_proxy_field_legacy on clean and fresh site.
Also partially revert 501c443d, which added this BT5 in tests, while it is not supposed to be needed anymore.