MM-53032: Fix module path after repo rename (#23689)

It was a good decision in hindsight to keep the public module as 0.x
because this would have been a breaking change again.

https://mattermost.atlassian.net/browse/MM-53032
```release-note
Changed the Go module path from github.com/mattermost/mattermost-server/server/v8 to github.com/mattermost/mattermost/server/v8.

For the public facing module, it's path is also changed from github.com/mattermost/mattermost-server/server/public to github.com/mattermost/mattermost/server/public
```

server/channels/app/telemetry.go

@@ -3,7 +3,7 @@
 
 package app
 
-import "github.com/mattermost/mattermost-server/server/v8/platform/services/telemetry"
+import "github.com/mattermost/mattermost/server/v8/platform/services/telemetry"
 
 func (s *Server) GetTelemetryService() *telemetry.TelemetryService {
 	return s.telemetryService