[chore][pkg/stanza] Remove unlimited memory for file paths

[djaglowski]

Follows #27823

This PR removes a list of all previously seen paths. The problem with this list is twofold. Primarily, it is unlimited in size. Although minor, this could grow indefinitely in some situations. Secondarily, it adds unnecessary complexity to the codebase.

The new approach simply logs a message whenever we open a file with contents which we've not seen in recent memory. Basically, it relies on the same mechanisms we use for tracking files for the purpose of whether or not to read them. While this is a slight change in user-facing functionality, I think it is reasonable considering the benefits.

[swiatekm]

LGTM

[atoulme]

In my opinion this is worthy of a changelog. Our field folks really like those logs to make sure they have the right files reporting in, and they will be disoriented with this change. Just adding a bit to the changelog will help them make sense of this change.

[andrzej-stencel]

Can you explain why this is marked as a breaking change? Should users (which users) perform an action when upgrading?

[swiatekm]

@astencel-sumo The receiver may now emit the same info log line about starting to watch a file multiple times for the same file in some circumstances. Though I agree we could do with a more succinct explanation of this change.

[djaglowski]

I marked it as breaking based upon @atoulme's comment regarding field teams relying on specific behaviors. I'm open to changing it of course.

[vasireddy99]

@astencel-sumo The receiver may now emit the same info log line about starting to watch a file multiple times for the same file in some circumstances. Though I agree we could do with a more succinct explanation of this change.

thanks for the explanation, can you please explain with an example circumstance where the receiver may emit same info is emitted. I think you meant this line right.