[Epic] Eager delta join experimentation and client analysis

[lfest]

Validate the eager delta join optimization in specific client settings. This will also incorporate experimentation.

### Tasks
- [ ] https://github.com/MaterializeInc/materialize/pull/25026
- [ ] https://github.com/MaterializeInc/materialize/pull/25473
- [ ] https://github.com/MaterializeInc/cloud/pull/8779
- [x] https://github.com/MaterializeInc/materialize/pull/26308
- [x] Identify prospects based on an `mzexplore` run
- [x] Execute experiments using #25273
- [x] Rollout to production

### Follow-ups
- [ ] Figure out what causes of higher latency when using eager delta joins