MM-22051: Remove ToJson from model (part 1) (#18005)

https://mattermost.atlassian.net/browse/MM-22051

```release-note
Removed the following methods/functions:
(ad *AccessData) ToJson()
(ar *AccessResponse) ToJson()
(ar *AnalyticsRow) ToJson()
(ar AnalyticsRows) ToJson()
(o *Audit) ToJson()
(o Audits) ToJson()
(ad *AuthData) ToJson()
(ar *AuthorizeRequest) ToJson()
(o *ChannelPatch) ToJson()
(o *ChannelsWithCount) ToJson()
(o *ChannelCounts) ToJson()
(o *ChannelData) ToJson()
(o *ChannelMembers) ToJson()
(o *ChannelUnread) ToJson()
(o *ChannelUnreadAt) ToJson()
(o *ChannelStats) ToJson()
(o *ChannelView) ToJson()
(o *ChannelViewResponse) ToJson()
(o *ClusterDiscovery) ToJson()
(ci *ClusterInfo) ToJson()
(cs *ClusterStats) ToJson()
(o *Command) ToJson()
CommandListToJson(l []*Command) string
(o *CommandArgs) ToJson()
(cmr *CommandMoveRequest) ToJson()
(o *CommandResponse) ToJson()
(c *Compliance) ToJson()
(c Compliances) ToJson()
(o *Config) ToJson()
EmojiListToJson(emojiList []*Emoji)
```

model/config.go

@@ -3159,18 +3159,18 @@ type Config struct {
 }
 
 func (o *Config) Clone() *Config {
+	buf, err := json.Marshal(o)
+	if err != nil {
+		panic(err)
+	}
 	var ret Config
-	if err := json.Unmarshal([]byte(o.ToJson()), &ret); err != nil {
+	err = json.Unmarshal(buf, &ret)
+	if err != nil {
 		panic(err)
 	}
 	return &ret
 }
 
-func (o *Config) ToJson() string {
-	b, _ := json.Marshal(o)
-	return string(b)
-}
-
 func (o *Config) ToJsonFiltered(tagType, tagValue string) string {
 	filteredConfigMap := structToMapFilteredByTag(*o, tagType, tagValue)
 	for key, value := range filteredConfigMap {