Wallet-app provides end-users an exit button on offers that have `exit: { waived: null }` in the proposal

[WietzeSlagman]

Describe the bug

Offers can have several exit clauses defined for them, one of them being waived meaning that only the creating smart-contract can exit this created offer. Currently the wallet-app displays an exit button for these offers and attempts to create an exit offer transaction, which fails.

To Reproduce

Steps to reproduce the behavior:

1. Create a long-living offer which has exit: { waived: null } in the proposal
2. navigate to wallet.agoric.app
3. On the created offer press the exit button
4. See transaction popping upon Keplr
5. Pressing approve on the transaction creates an error on-chain

Expected behavior

Expect any offer that has the exit: { waived: null } in the proposal to not have a clickable exit button in the wallet-app frontend

Platform Environment

• MacOS, node 18.16
• @agoric/cosmic-swingset@0.41.3-593-gde82c94a0

Additional context

Screenshots