feat: add Equal methods for AssetInfo and ChainInfo types

x/did/types/types.go

@@ -0,0 +1,15 @@
+package types
+
+func (a *AssetInfo) Equal(b *AssetInfo) bool {
+	if a == nil && b == nil {
+		return true
+	}
+	return false
+}
+
+func (c *ChainInfo) Equal(b *ChainInfo) bool {
+	if c == nil && b == nil {
+		return true
+	}
+	return false
+}