Apply Sanitizers Immediately

[scbedd]

@timovv was investigating Azure/azure-sdk-for-js#18222

Essentially, sanitizers apply during record when we stop the recording. During playback, sanitizers are applied to each request prior to matching against the recordings.

There are complicating factors here. We have sanitizers that rely on more than just an individual request/response pair. See ContinuationSanitizer. We should properly apply those sanitizers that do operate on individual entries during the recording, then apply all session-level sanitizers when saving to disk.

This makes sense because to not apply individual sanitizers to each request means that if a sanitizer is added while a recording is in progress than it should only apply to the requests after it was added. Example Timeline below

• Admin/AddSanitizer to add sanitizer A
• Record/Start -> returns recordingid
• Record Request 1
• Admin/AddSanitizer to add sanitizer B
• Record Request 2

Request 1 should be sanitized by A only. Request 2 should be sanitized by A AND B.

With the way the proxy currently works, A and B will apply to both regardless.