mod+kvdb+channeldb: use btcwallet new DB interface

Depends on btcsuite/btcwallet#757.
Pulls in the updated version of btcwallet and walletdb that have the DB
interface enhanced by their own View() and Update() methods with the
reset callback/closure supported out of the box. That way the global
package-level View() and Update() functions now become pure redirects.

kvdb/go.mod

@@ -2,7 +2,7 @@ module github.com/lightningnetwork/lnd/kvdb
 
 require (
 	github.com/btcsuite/btclog v0.0.0-20170628155309-84c8d2346e9f
-	github.com/btcsuite/btcwallet/walletdb v1.3.5-0.20210513043850-3a2f12e3a954
+	github.com/btcsuite/btcwallet/walletdb v1.3.6-0.20210803004036-eebed51155ec
 	github.com/lightningnetwork/lnd/healthcheck v1.0.0
 	github.com/stretchr/testify v1.7.0
 	go.etcd.io/bbolt v1.3.6