Implement GET channels endpoints for APIv4 (#5363)

* implement get channels endpoints and updated drivers and unittests

* removed channel deletion on tear down, removed manage permission on get channels endpoints, and updated utils to add constant channel length

* added constants for user, team and channel length, updated context to use the model functions

* make sure team name length should be less than the minimum length and revert underscore to team name validity

* changed post test condition from notfound to unauthorized

api4/params.go

@@ -17,18 +17,20 @@ const (
 )
 
 type ApiParams struct {
-	UserId    string
-	TeamId    string
-	ChannelId string
-	PostId    string
-	FileId    string
-	CommandId string
-	HookId    string
-	EmojiId   string
-	Email     string
-	Username  string
-	Page      int
-	PerPage   int
+	UserId      string
+	TeamId      string
+	ChannelId   string
+	PostId      string
+	FileId      string
+	CommandId   string
+	HookId      string
+	EmojiId     string
+	Email       string
+	Username    string
+	TeamName    string
+	ChannelName string
+	Page        int
+	PerPage     int
 }
 
 func ApiParamsFromRequest(r *http.Request) *ApiParams {
@@ -76,6 +78,14 @@ func ApiParamsFromRequest(r *http.Request) *ApiParams {
 		params.Username = val
 	}
 
+	if val, ok := props["team_name"]; ok {
+		params.TeamName = val
+	}
+
+	if val, ok := props["channel_name"]; ok {
+		params.ChannelName = val
+	}
+
 	if val, err := strconv.Atoi(r.URL.Query().Get("page")); err != nil {
 		params.Page = PAGE_DEFAULT
 	} else {