DM-45907: Decrease page size for queries

[dhirving]

Decrease query driver's default page size. Queries were consuming excessive memory on Butler server, and lowering this value does not seem to make queries any slower. This reduces memory consumption for a dataset query with dimension records from ~120MB to ~30MB per in-flight query.

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes
• (if changing dimensions.yaml) make a copy of dimensions.yaml in configs/old_dimensions

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.54%. Comparing base (11dbc91) to head (d249b51).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1064   +/-   ##
=======================================
  Coverage   89.54%   89.54%           
=======================================
  Files         359      359           
  Lines       46473    46473           
  Branches     9558     9558           
=======================================
  Hits        41612    41612           
  Misses       3511     3511           
  Partials     1350     1350           

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