[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/public/model/client4_test.go

@@ -4,11 +4,13 @@
 package model
 
 import (
+	"context"
 	"encoding/json"
 	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -73,7 +75,7 @@ func TestClient4CreatePost(t *testing.T) {
 	}))
 
 	client := NewAPIv4Client(server.URL)
-	_, resp, err := client.CreatePost(post)
+	_, resp, err := client.CreatePost(context.Background(), post)
 	assert.NoError(t, err)
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 }
@@ -100,7 +102,52 @@ func TestClient4SetToken(t *testing.T) {
 	client := NewAPIv4Client(server.URL)
 	client.SetToken(expected)
 
-	_, resp, err := client.GetMe("")
+	_, resp, err := client.GetMe(context.Background(), "")
 	assert.NoError(t, err)
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 }
+
+func TestClient4RequestCancellation(t *testing.T) {
+	t.Run("cancel before making the reqeust", func(t *testing.T) {
+		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			t.Fatal("request should not hit the server")
+		}))
+
+		client := NewAPIv4Client(server.URL)
+
+		ctx, cancel := context.WithCancel(context.Background())
+
+		cancel()
+
+		_, resp, err := client.GetMe(ctx, "")
+		assert.Error(t, err)
+		assert.ErrorIs(t, err, context.Canceled)
+		assert.Nil(t, resp)
+	})
+
+	t.Run("cancel after making the reqeust", func(t *testing.T) {
+
+		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			time.Sleep(100 * time.Millisecond)
+			t.Fatal("request should not hit the server")
+		}))
+
+		client := NewAPIv4Client(server.URL)
+
+		ctx, cancel := context.WithCancel(context.Background())
+
+		done := make(chan struct{})
+		go func() {
+			_, resp, err := client.GetMe(ctx, "")
+			assert.Error(t, err)
+			assert.ErrorIs(t, err, context.Canceled)
+			assert.Nil(t, resp)
+
+			done <- struct{}{}
+
+		}()
+		cancel()
+
+		<-done
+	})
+}