[MM-49989] Pass a context.Context to Client4 methods (#22922)

* Migrate all method in model/client4.go to accept a context.Context

* Fix th.*Client

* Fix remaining issues

* Empty commit to triger CI

* Fix test

* Add cancellation test

* Test that returned error is context.Canceled

* Fix bad merge

* Update mmctl code

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/slashcommands/auto_users.go

@@ -4,6 +4,7 @@
 package slashcommands
 
 import (
+	"context"
 	"errors"
 	"net/http"
 
@@ -42,18 +43,18 @@ func NewAutoUserCreator(a *app.App, client *model.Client4, team *model.Team) *Au
 
 // Basic test team and user so you always know one
 func CreateBasicUser(a *app.App, client *model.Client4) error {
-	found, _, _ := client.TeamExists(BTestTeamName, "")
+	found, _, _ := client.TeamExists(context.Background(), BTestTeamName, "")
 	if found {
 		return nil
 	}
 
 	newteam := &model.Team{DisplayName: BTestTeamDisplayName, Name: BTestTeamName, Email: BTestTeamEmail, Type: BTestTeamType}
-	basicteam, _, err := client.CreateTeam(newteam)
+	basicteam, _, err := client.CreateTeam(context.Background(), newteam)
 	if err != nil {
 		return err
 	}
 	newuser := &model.User{Email: BTestUserEmail, Nickname: BTestUserName, Password: BTestUserPassword}
-	ruser, _, err := client.CreateUser(newuser)
+	ruser, _, err := client.CreateUser(context.Background(), newuser)
 	if err != nil {
 		return err
 	}