MM-21357: Use typed constant for channel types (#17928)

* MM-21357: Use typed constant for channel types

https://mattermost.atlassian.net/browse/MM-21357

```release-note
- Introduced a new type ChannelType for all channel types.
- Updated the Client4.UpdateChannelPrivacy method to ChannelType.
```

* Address review comments

```release-note
NONE
```

* telemetry fix

```release-note
NONE
```

store/sqlstore/integrity.go

@@ -215,7 +215,7 @@ func checkTeamsChannelsIntegrity(ss *SqlStore) model.IntegrityCheckResult {
 		parentIdAttr: "TeamId",
 		childName:    "Channels",
 		childIdAttr:  "Id",
-		filter:       sq.NotEq{"CT.Type": []string{model.ChannelTypeDirect, model.ChannelTypeGroup}},
+		filter:       sq.NotEq{"CT.Type": []model.ChannelType{model.ChannelTypeDirect, model.ChannelTypeGroup}},
 	})
 	res2 := checkParentChildIntegrity(ss, relationalCheckConfig{
 		parentName:         "Teams",
@@ -223,7 +223,7 @@ func checkTeamsChannelsIntegrity(ss *SqlStore) model.IntegrityCheckResult {
 		childName:          "Channels",
 		childIdAttr:        "Id",
 		canParentIdBeEmpty: true,
-		filter:             sq.Eq{"CT.Type": []string{model.ChannelTypeDirect, model.ChannelTypeGroup}},
+		filter:             sq.Eq{"CT.Type": []model.ChannelType{model.ChannelTypeDirect, model.ChannelTypeGroup}},
 	})
 	data1 := res1.Data.(model.RelationalIntegrityCheckData)
 	data2 := res2.Data.(model.RelationalIntegrityCheckData)