In #5120, the `nimbus_beacon_node deposits exit` command was updated for
compatibility with EIP-7044, which forces signatures to be made using
`CAPELLA_FORK_VERSION` regardless of the `VoluntaryExit`'s `epoch` after
Deneb is activated.
This update had a regression, as an older mechanism was used to fetch
`RuntimeConfig`, resulting in an encoding issue (#5362). This was then
fixed in #5370, restoring general `deposits exit` functionality.
However, the logic from #5120 has another flaw, as it uses an incorrect
fork version based on the pre-Deneb logic even after Deneb and EIP-7044
are activated. Fix this now, so that `deposits exit` continues to work
correctly after Deneb activates.
457e68eab3