Update Celestia-appd to `v2.1.2`

[ljoss17]

Status

Currently failing with unknown error:

error: builder for '/nix/store/2h100pb8ml85vi5wqxkgvk88cgl0l9hb-celestia-app.drv' failed with exit code 1;
       last 10 log lines:
       > github.com/cosmos/cosmos-sdk/x/auth/posthandler
       > github.com/cosmos/cosmos-sdk/x/nft
       > github.com/cosmos/cosmos-sdk/x/nft/keeper
       > github.com/cosmos/cosmos-sdk/x/nft/client/cli
       > github.com/cosmos/cosmos-sdk/x/nft/simulation
       > github.com/cosmos/cosmos-sdk/x/nft/module
       > github.com/cosmos/cosmos-sdk/simapp
       > github.com/cosmos/cosmos-sdk/testutil
       > github.com/cosmos/cosmos-sdk/x/genutil/migrations/v043
       > github.com/cosmos/cosmos-sdk/x/genutil/migrations/v046