fix: rotate session id when reset is called

[marandaneto]

💡 Motivation and Context

found during the #167 testing
when reset is called, the session id was set to null, so the next events wouldn't contain a session id anymore, in this case, the correct behaviour would be just rotating the session id.
this would affect session recording as well.

💚 How did you test it?

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.