multi: replace DefaultDustLimit with script-specific DustLimitForSize

This commit updates call-sites to use the proper dust limits for
various script types. This also updates the default dust limit used
in the funding flow to be 354 satoshis instead of 573 satoshis.

lnwallet/parameters_test.go

@@ -0,0 +1,56 @@
+package lnwallet
+
+import (
+	"testing"
+
+	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/input"
+	"github.com/stretchr/testify/require"
+)
+
+// TestDustLimitForSize tests that we receive the expected dust limits for
+// various script types from btcd's GetDustThreshold function.
+func TestDustLimitForSize(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name          string
+		size          int
+		expectedLimit btcutil.Amount
+	}{
+		{
+			name:          "p2pkh dust limit",
+			size:          input.P2PKHSize,
+			expectedLimit: btcutil.Amount(546),
+		},
+		{
+			name:          "p2sh dust limit",
+			size:          input.P2SHSize,
+			expectedLimit: btcutil.Amount(540),
+		},
+		{
+			name:          "p2wpkh dust limit",
+			size:          input.P2WPKHSize,
+			expectedLimit: btcutil.Amount(294),
+		},
+		{
+			name:          "p2wsh dust limit",
+			size:          input.P2WSHSize,
+			expectedLimit: btcutil.Amount(330),
+		},
+		{
+			name:          "unknown witness limit",
+			size:          input.UnknownWitnessSize,
+			expectedLimit: btcutil.Amount(354),
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+
+		t.Run(test.name, func(t *testing.T) {
+			dustlimit := DustLimitForSize(test.size)
+			require.Equal(t, test.expectedLimit, dustlimit)
+		})
+	}
+}