Premium SKU (#30396)

* Added premium SKU

* removed duplicate enterprise license check functions

* Added license check on API layer

* lint fix

* lint fix

* refactured signature:

* test: Add comprehensive tests for license tier check functions

* fixed test

* text update

* optimised license checks

* fixedf test

* Updated license valid function

* webapp license checks

* handling prekium SKU in webappp:

* added plugin api method and general refactoring

* Updated tests

---------

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

server/channels/api4/channel_test.go

@@ -810,7 +810,7 @@ func TestPatchChannel(t *testing.T) {
 	t.Run("Should be able to configure channel banner on a channel", func(t *testing.T) {
 		client.Logout(context.Background())
 		th.LoginBasic()
-		th.App.Srv().SetLicense(model.NewTestLicenseSKU(model.LicenseShortSkuEnterprise))
+		th.App.Srv().SetLicense(model.NewTestLicenseSKU(model.LicenseShortSkuPremium))
 		defer func() {
 			th.App.Srv().RemoveLicense()
 		}()
@@ -845,7 +845,7 @@ func TestPatchChannel(t *testing.T) {
 	t.Run("Cannot enable channel banner without configuring it", func(t *testing.T) {
 		client.Logout(context.Background())
 		th.LoginBasic()
-		th.App.Srv().SetLicense(model.NewTestLicenseSKU(model.LicenseShortSkuEnterprise))
+		th.App.Srv().SetLicense(model.NewTestLicenseSKU(model.LicenseShortSkuPremium))
 		defer func() {
 			th.App.Srv().RemoveLicense()
 		}()
@@ -905,7 +905,7 @@ func TestPatchChannel(t *testing.T) {
 	t.Run("Cannot configure channel banner on a DM channel", func(t *testing.T) {
 		client.Logout(context.Background())
 		th.LoginBasic()
-		th.App.Srv().SetLicense(model.NewTestLicenseSKU(model.LicenseShortSkuEnterprise))
+		th.App.Srv().SetLicense(model.NewTestLicenseSKU(model.LicenseShortSkuPremium))
 		defer func() {
 			th.App.Srv().RemoveLicense()
 		}()
@@ -932,7 +932,7 @@ func TestPatchChannel(t *testing.T) {
 	t.Run("Cannot configure channel banner on a GM channel", func(t *testing.T) {
 		client.Logout(context.Background())
 		th.LoginBasic()
-		th.App.Srv().SetLicense(model.NewTestLicenseSKU(model.LicenseShortSkuEnterprise))
+		th.App.Srv().SetLicense(model.NewTestLicenseSKU(model.LicenseShortSkuPremium))
 		defer func() {
 			th.App.Srv().RemoveLicense()
 		}()
@@ -5728,7 +5728,7 @@ func TestCanEditChannelBanner(t *testing.T) {
 	})
 
 	t.Run("when channel type is direct message", func(t *testing.T) {
-		license := model.NewTestLicenseSKU(model.LicenseShortSkuEnterprise)
+		license := model.NewTestLicenseSKU(model.LicenseShortSkuPremium)
 		channel := &model.Channel{
 			Type: model.ChannelTypeDirect,
 		}
@@ -5741,7 +5741,7 @@ func TestCanEditChannelBanner(t *testing.T) {
 	})
 
 	t.Run("when channel type is group message", func(t *testing.T) {
-		license := model.NewTestLicenseSKU(model.LicenseShortSkuEnterprise)
+		license := model.NewTestLicenseSKU(model.LicenseShortSkuPremium)
 		channel := &model.Channel{
 			Type: model.ChannelTypeGroup,
 		}
@@ -5753,7 +5753,7 @@ func TestCanEditChannelBanner(t *testing.T) {
 	})
 
 	t.Run("when channel type is open and license is valid", func(t *testing.T) {
-		license := model.NewTestLicenseSKU(model.LicenseShortSkuEnterprise)
+		license := model.NewTestLicenseSKU(model.LicenseShortSkuPremium)
 		channel := &model.Channel{
 			Type: model.ChannelTypeOpen,
 		}
@@ -5763,7 +5763,7 @@ func TestCanEditChannelBanner(t *testing.T) {
 	})
 
 	t.Run("when channel type is private and license is valid", func(t *testing.T) {
-		license := model.NewTestLicenseSKU(model.LicenseShortSkuEnterprise)
+		license := model.NewTestLicenseSKU(model.LicenseShortSkuPremium)
 		channel := &model.Channel{
 			Type: model.ChannelTypePrivate,
 		}