UnmarshalJSON error on JSON-RPC

[danburck]

Current Situation

Some JSON-RPC endpoints are responding with the following error:

Jun 16 15:34:28 evmos-clust-ar-pub-testnet evmosd[11828]: 3:34PM INF Served eth_call conn=10.128.0.218:59310 duration=3367.218939 err="rpc error: code =Unknown desc = UnmarshalJSON cannot decode empty bytes: panic" module=geth reqid=4

Possible Solution

We need to change all the GetParams functions to use the method defined below to prevent unnecessary panics.
@fedekunze implemented a fix on the SDK with tests that can be used once the new point release is updated: cosmos/cosmos-sdk#12615

func (k Keeper) GetParams(ctx sdk.Context) (params types.Params) {
	for _, pair := range params.ParamSetPairs() {
		k.paramSpace.GetIfExists(ctx, pair.Key, pair.Value)
	}

	return params
}