Gov: setting a new fork escrow contract might lead to lost tokens

[eladmallel]

Based on this C4 issue found as part of the DAO V3 audit: code-423n4/2023-07-nounsdao-findings#56.

In the current design if a token holder wants to withdraw their tokens from escrow, they have to call a DAO function which then calls the escrow; the escrow's withdraw function only allows the DAO to call it. If the DAO passes a proposal to swap the escrow contract with a new one, tokens held in the old escrow contract can only be withdrawn if the governor (DAO logic) is upgraded with a new function allowing token holders to call the old escrow's withdraw function. Without such an upgrade those token holders do not have access to their tokens.

A solution would be to allow any token holder to call the withdraw function directly on the escrow contract.