Submitting a proposal without signature can break the proposal page

[ivanzhelyazkov]

There are two functions supported for submitting proposals using the OUSD governance system:

function propose(
        address[] memory targets,
        uint256[] memory values,
        bytes[] memory calldatas,
        string memory description
    )

function propose(
       address[] memory targets,
       uint256[] memory values,
       string[] memory signatures,
       bytes[] memory calldatas,
       string memory description
   ) 

Submitting a proposal using the first method may break the proposal page because the FE relies on the signature to exist in order to read the proposal data. Example of that on staging:
https://ousd-governance-goerli.herokuapp.com/proposals/16204839399612801854620380292150922398934072453886132313980681190386539950238
Proposals without signatures could be read as invalid by the FE, or could skip the call data validation part.