[MM-57356] Make use of go1.21 features (#26620)

server/channels/store/storetest/group_store.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"math"
+	"slices"
 	"sort"
 	"strings"
 	"testing"
@@ -17,7 +18,6 @@ import (
 
 	"github.com/mattermost/mattermost/server/public/model"
 	"github.com/mattermost/mattermost/server/public/shared/request"
-	pUtils "github.com/mattermost/mattermost/server/public/utils"
 	"github.com/mattermost/mattermost/server/v8/channels/store"
 )
 
@@ -4826,7 +4826,7 @@ func groupTestpUpdateMembersRoleTeam(t *testing.T, rctx request.CTX, ss store.St
 			require.GreaterOrEqual(t, len(members), 4) // sanity check for team membership
 
 			for _, member := range members {
-				if pUtils.Contains(tt.inUserIDs, member.UserId) {
+				if slices.Contains(tt.inUserIDs, member.UserId) {
 					require.True(t, member.SchemeAdmin)
 				} else {
 					require.False(t, member.SchemeAdmin)
@@ -4936,7 +4936,7 @@ func groupTestpUpdateMembersRoleChannel(t *testing.T, rctx request.CTX, ss store
 			require.GreaterOrEqual(t, len(members), 4) // sanity check for channel membership
 
 			for _, member := range members {
-				if pUtils.Contains(tt.inUserIDs, member.UserId) {
+				if slices.Contains(tt.inUserIDs, member.UserId) {
 					require.True(t, member.SchemeAdmin)
 				} else {
 					require.False(t, member.SchemeAdmin)