[server] Remove useless 'is None' checks 'pb' is never none since 3386fd89c914 when support for the 'APYCOT_ROOT' env var was removed.

[security] check attributes: dispatch on the "add" action if entity was just created cw_set on a just-created entity (i.e. created in the same transaction) should behave the same as setting the attribute directly on creation: check the 'add' permissions, not 'update'. Closes #4740310.

[doc] Add BigInt to the list of built-in types

[devtools] call turn_repo_off in tearDown (closes #4673491) lets it catch leaked sessions even when running a single test