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

server/channels/app/channel.go

@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"slices"
 	"strings"
 
 	"github.com/mattermost/mattermost/server/v8/channels/utils"
@@ -18,7 +19,6 @@ import (
 	"github.com/mattermost/mattermost/server/public/shared/i18n"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
 	"github.com/mattermost/mattermost/server/public/shared/request"
-	pUtils "github.com/mattermost/mattermost/server/public/utils"
 	"github.com/mattermost/mattermost/server/v8/channels/store"
 	"github.com/mattermost/mattermost/server/v8/channels/store/sqlstore"
 )
@@ -1036,7 +1036,7 @@ func (a *App) PatchChannelModerationsForChannel(c request.CTX, channel *model.Ch
 
 	for _, channelModerationPatch := range channelModerationsPatch {
 		permissionModified := *channelModerationPatch.Name
-		if channelModerationPatch.Roles.Guests != nil && pUtils.Contains(model.ChannelModeratedPermissionsChangedByPatch(guestRole, guestRolePatch), permissionModified) {
+		if channelModerationPatch.Roles.Guests != nil && slices.Contains(model.ChannelModeratedPermissionsChangedByPatch(guestRole, guestRolePatch), permissionModified) {
 			if *channelModerationPatch.Roles.Guests {
 				c.Logger().Info("Permission enabled for guests.", mlog.String("permission", permissionModified), mlog.String("channel_id", channel.Id), mlog.String("channel_name", channel.Name))
 			} else {
@@ -1044,7 +1044,7 @@ func (a *App) PatchChannelModerationsForChannel(c request.CTX, channel *model.Ch
 			}
 		}
 
-		if channelModerationPatch.Roles.Members != nil && pUtils.Contains(model.ChannelModeratedPermissionsChangedByPatch(memberRole, memberRolePatch), permissionModified) {
+		if channelModerationPatch.Roles.Members != nil && slices.Contains(model.ChannelModeratedPermissionsChangedByPatch(memberRole, memberRolePatch), permissionModified) {
 			if *channelModerationPatch.Roles.Members {
 				c.Logger().Info("Permission enabled for members.", mlog.String("permission", permissionModified), mlog.String("channel_id", channel.Id), mlog.String("channel_name", channel.Name))
 			} else {