Adds Shared Channel related API endpoints (#27436)

* Adds Shared Channel management API endpoints

New endpoints for the following routes are added:

- Get Shared Channel Remotes by Remote Cluster at `GET
/api/v4/remotecluster/{remote_id}/sharedchannelremotes`
- Invite Remote Cluster to Channel at `POST
/api/v4/remotecluster/{remote_id}/channels/invite`
- Uninvite Remote Cluster to Channel at `POST
/api/v4/remotecluster/{remote_id}/channels/uninvite`

These endpoints are planned to be used from the system console, and
gated through the `manage_secure_connections` permission.

* Adds i18n messages for API errors

* Fix pagination flaky test

* Fix linter

* Adds the posibility of filtering shared channel remotes by home

---------

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

server/channels/app/app_iface.go

@@ -817,7 +817,7 @@ type AppIface interface {
 	GetSharedChannel(channelID string) (*model.SharedChannel, error)
 	GetSharedChannelRemote(id string) (*model.SharedChannelRemote, error)
 	GetSharedChannelRemoteByIds(channelID string, remoteID string) (*model.SharedChannelRemote, error)
-	GetSharedChannelRemotes(opts model.SharedChannelRemoteFilterOpts) ([]*model.SharedChannelRemote, error)
+	GetSharedChannelRemotes(page, perPage int, opts model.SharedChannelRemoteFilterOpts) ([]*model.SharedChannelRemote, error)
 	GetSharedChannelRemotesStatus(channelID string) ([]*model.SharedChannelRemoteStatus, error)
 	GetSharedChannels(page int, perPage int, opts model.SharedChannelFilterOpts) ([]*model.SharedChannel, *model.AppError)
 	GetSharedChannelsCount(opts model.SharedChannelFilterOpts) (int64, error)

server/channels/app/opentracing/opentracing_layer.go

@@ -9744,7 +9744,7 @@ func (a *OpenTracingAppLayer) GetSharedChannelRemoteByIds(channelID string, remo
 	return resultVar0, resultVar1
 }
 
-func (a *OpenTracingAppLayer) GetSharedChannelRemotes(opts model.SharedChannelRemoteFilterOpts) ([]*model.SharedChannelRemote, error) {
+func (a *OpenTracingAppLayer) GetSharedChannelRemotes(page int, perPage int, opts model.SharedChannelRemoteFilterOpts) ([]*model.SharedChannelRemote, error) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetSharedChannelRemotes")
 
@@ -9756,7 +9756,7 @@ func (a *OpenTracingAppLayer) GetSharedChannelRemotes(opts model.SharedChannelRe
 	}()
 
 	defer span.Finish()
-	resultVar0, resultVar1 := a.app.GetSharedChannelRemotes(opts)
+	resultVar0, resultVar1 := a.app.GetSharedChannelRemotes(page, perPage, opts)
 
 	if resultVar1 != nil {
 		span.LogFields(spanlog.Error(resultVar1))

server/channels/app/shared_channel.go

@@ -137,8 +137,8 @@ func (a *App) GetSharedChannelRemoteByIds(channelID string, remoteID string) (*m
 	return a.Srv().Store().SharedChannel().GetRemoteByIds(channelID, remoteID)
 }
 
-func (a *App) GetSharedChannelRemotes(opts model.SharedChannelRemoteFilterOpts) ([]*model.SharedChannelRemote, error) {
-	return a.Srv().Store().SharedChannel().GetRemotes(opts)
+func (a *App) GetSharedChannelRemotes(page, perPage int, opts model.SharedChannelRemoteFilterOpts) ([]*model.SharedChannelRemote, error) {
+	return a.Srv().Store().SharedChannel().GetRemotes(page*perPage, perPage, opts)
 }
 
 // HasRemote returns whether a given channelID is present in the channel remotes or not.