Bugfix: RemoteFileSyncer handling of error responses

[Net-burst]

🔧 Type of changes

• new bid adapter
• update bid adapter
• new feature
• new analytics adapter
• new module
• bugfix
• documentation
• configuration
• tech debt (test coverage, refactorings, etc.)

✨ What's the context?

RemoteFileSyncer never validated the server response status code and always saved the response body unless the request has timed out. This led to RemoteFileSyncer wiping perfectly valid files on periodic sync in case the remote server errors out for whatever reason.

🧠 Rationale behind the change

This PR adds a new check for 200 response status code before attempting to save the downloaded file.
Another bugfix here is that the RemoteFileSyncer now actually follows redirects.

🧪 Test plan

New logic is covered with unit tests.

🏎 Quality check

• Are your changes following our code style guidelines?
• Are there any breaking changes in your code?
• Does your test coverage exceed 90%?
• Are there any erroneous console logs, debuggers or leftover code in your changes?