Improve batched job progress indicator

[bencroker]

This PR improves the batched job progress indicator by making it work more like the base job progress indicator, meaning that the percentage and indicator will move from 0% to 100% across all batches, rather than once for each batch.

In this example, a sendout is being sent to 5 recipients with a batch size of 2 (to help demonstrate the issue).

Before:

The progress of 50% is calculated as step 1 of 2 items in the current batch.

After:

The progress of 80% is calculated as step 4 of 5 total items in the job.

Here’s a real-world example that shows how the percentage and the “step of total” being out of sync can be confusing:

Source: putyourlightson/craft-campaign#464

Ideally it would be backported to 4.x too.

[bossanova808]

This is great to see - the current behaviour is very confusing (at least in this context, likely any long running, countable batch process).

[brandonkelly]

Thanks!! Cherry-picked your commit into the 4.9 branch (8a131a3), and also merged that into 5.1.

[brandonkelly]

4.9 and 5.1 are out now with that change.