[Sub-Organizations] Fix point-of-contact on HCB's end

[YodaLightsabr]

can we set it so that suborgs dont need a contract signer for certain hq things? we are running into the issue hcb is thinking the person inviting/creating stuff for people is an hcb admin, so reem got assigned as both the contract signee AND hcb PoC for her contract. same thing with dev inviting augie to a event suborg, it required Dev to sign off as the HCB PoC. if not could we default it to be like if the user isnt an hcb admin, it defaults to the HCB PoC being bank@?

https://hackclub.slack.com/archives/C026RKHLPNJ/p1765225576537719