Fix #1308: Remove dead dask.config.set() at module import time

The module-level call in ag3.py:

    dask.config.set(**{"array.slicing.split_native_chunks": False})

was historically present to silence a dask `PerformanceWarning` emitted
on certain slicing operations. On current dask (>=2025), the
`array.slicing.split_native_chunks` config key is unrecognised (returns
no default) and the associated `PerformanceWarning` has been removed
from `dask.array.slicing`. The setting therefore has no observable
effect in any currently-supported dask version.

Removing the line directly addresses the filed bug — `import
malariagen_data` no longer modifies global dask configuration — without
introducing scoped context managers or any other new machinery.

Verified:
- `import malariagen_data` leaves `dask.config.get('array.slicing.
  split_native_chunks', 'DEFAULT') == 'DEFAULT'`.
- `tests/anoph/test_snp_data.py` (193 tests), `test_frq.py`,
  `test_cnv_data.py`, `test_hapclust.py`, `test_dipclust.py`,
  `test_hap_data.py`, `test_aim_data.py` all pass with no new warnings;
  in particular no `PerformanceWarning` is emitted from any of the
  `da.take` / `da.compress` call sites in `util.py` or `snp_data.py`.
- pre-commit, ruff, ruff-format, mypy all clean.

Author: khushthecoder

malariagen_data/ag3.py

@@ -1,14 +1,10 @@
 import sys
 
-import dask
 import pandas as pd  # type: ignore
 import plotly.express as px  # type: ignore
 import malariagen_data
 from .anopheles import AnophelesDataResource
 
-# silence dask performance warnings
-dask.config.set(**{"array.slicing.split_native_chunks": False})  # type: ignore
-
 MAJOR_VERSION_NUMBER = 3
 MAJOR_VERSION_PATH = "v3"
 CONFIG_PATH = "v3-config.json"