Activity tab - Dedupe in-flight summary requests

[tonisevener]

Phabricator: https://phabricator.wikimedia.org/T417033

Notes

When watching network calls for instrumentation, I noticed a large influx of calls to the page/summary endpoint with the same title. For my particular account, it was partly due to a lot of edits to the same article (my user talk page). Since they are all distinct items on the timeline, they all tried fetching the summary at the same time. The existing caching didn't work yet because the first summary fetch had not yet completed.

This PR dedupes these by keeping track of a dictionary of in-flight requests. Once the first one starts, the next ones simply queue up the completion handler. Then once the first one completes, it calls all of the completion handlers.

Test Steps

1. Make several edits to the same article.
2. Re-launch the app, watch the network calls and ensure only one call is made to the summary endpoint (looks like https://en.wikipedia.org/api/rest_v1/page/summary/{article title}) per-title.

Screenshots/Videos

[Copilot]

Pull request overview

This PR aims to reduce duplicate REST page/summary calls by deduping concurrent (in-flight) summary requests per title for the Activity tab.

Changes:

• Updates the Growth Tasks data controller test to use the shared WMFArticleSummaryDataController instance (instead of constructing a new one), aligning with a singleton-based summary fetching approach.

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[l-olson1214]

LGTM! Should we set up some service like this that can be reused elsewhere (checks if something's in flight? Is that possible to make generic?)

[tonisevener]

LGTM! Should we set up some service like this that can be reused elsewhere (checks if something's in flight? Is that possible to make generic?)

Good idea, tracking this here.