feat: fix upgradeHander issue

[gyuguen]

We ran into an error situation during the Testnet deployment.

Jun 10 03:09:17 testnet-sentry panacead[3707341]: panic: cannot delete latest saved version (12)
Jun 10 03:09:17 testnet-sentry panacead[3707341]: goroutine 1 [running]:
Jun 10 03:09:17 testnet-sentry panacead[3707341]: github.com/cosmos/cosmos-sdk/store/rootmulti.(*Store).pruneStores(0xc0001cc460)
Jun 10 03:09:17 testnet-sentry panacead[3707341]:         /home/ubuntu/go/pkg/mod/github.com/medibloc/cosmos-sdk@v0.42.11-panacea.1/store/rootmulti/store.go:388 +0x26e

This error occurs when the following code is excuted.
https://github.com/cosmos/cosmos-sdk/blob/v0.42.11/store/rootmulti/store.go#L380

CosmosHub has solved this related problem as follows.
https://github.com/cosmos/gaia/blob/v5.0.8/app/app.go#L428

We also modified it with reference to this.

[inchori]

LGTM 👍

[youngjoon-lee]

danke