Refactor: func StringInSlice to slices.Contains (#24262)

* Refactor: Use generic to change func StringInSlice to Contains

* Refactor: Use generic to change func stringNotInSlice to Contains

Make utils.go (dir server/public/utils) and func Contains

* Refactor: Move func Contains from channels/utils to public/utils

Move func Contains from channels/utils to public/utils

Fix import declarations line

* Docs: Add a description of the Contains function

* Test: add TestContains

Add a test code for a Contain function

server/channels/app/channel.go

@@ -15,11 +15,12 @@ import (
 	"github.com/mattermost/mattermost/server/public/plugin"
 	"github.com/mattermost/mattermost/server/public/shared/i18n"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
+	pUtils "github.com/mattermost/mattermost/server/public/utils"
+
 	"github.com/mattermost/mattermost/server/v8/channels/app/request"
 	"github.com/mattermost/mattermost/server/v8/channels/product"
 	"github.com/mattermost/mattermost/server/v8/channels/store"
 	"github.com/mattermost/mattermost/server/v8/channels/store/sqlstore"
-	"github.com/mattermost/mattermost/server/v8/channels/utils"
 )
 
 // channelsWrapper provides an implementation of `product.ChannelService` to be used by products.
@@ -1103,7 +1104,7 @@ func (a *App) PatchChannelModerationsForChannel(c request.CTX, channel *model.Ch
 
 	for _, channelModerationPatch := range channelModerationsPatch {
 		permissionModified := *channelModerationPatch.Name
-		if channelModerationPatch.Roles.Guests != nil && utils.StringInSlice(permissionModified, model.ChannelModeratedPermissionsChangedByPatch(guestRole, guestRolePatch)) {
+		if channelModerationPatch.Roles.Guests != nil && pUtils.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 {
@@ -1111,7 +1112,7 @@ func (a *App) PatchChannelModerationsForChannel(c request.CTX, channel *model.Ch
 			}
 		}
 
-		if channelModerationPatch.Roles.Members != nil && utils.StringInSlice(permissionModified, model.ChannelModeratedPermissionsChangedByPatch(memberRole, memberRolePatch)) {
+		if channelModerationPatch.Roles.Members != nil && pUtils.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 {