Backport of core: limit job GC batch size to match other GC batches into release/1.10.x

[hc-github-team-nomad-core]

Backport

This PR is auto-generated from #26974 to be assessed for backporting due to the inclusion of the label backport/1.10.x.

The below text is copied from the body of the original PR.

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In the core scheduler we have several object types where we can delete them by ID. We batch up to 7281 UUIDs because this works out to be about 256 KiB per request, which is well below the maximum Raft log entry size we want to have. When we GC jobs we use this same constant to size the batch, but the request body is not a list of UUIDs but instead a map of namespaced job IDs to a pointer to a struct. This pushes the batch size into 746 KiB (assuming UUID-sized job names), which is going to impact performance if GC happens during large volumes of short-lived dispatch work where users may be GC'ing jobs frequently.

Limit the batch size for JobBatchDeregisterRequest to roughly the same size as the requests that are lists of UUIDs.

Ref: https://hashicorp.atlassian.net/browse/NMD-1041

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  • see core: limit job GC batch size to match other GC batches #26974 (comment)
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Overview of commits

• 12f6941