ci: update AWS runner configuration for region and image

[grst]

Update CI Run configuration after switch to scverse AWS account and runner image from scverse/cpu-ci-config.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.32%. Comparing base (c53c8ea) to head (04d9a79).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #181      +/-   ##
==========================================
- Coverage   99.33%   97.32%   -2.01%     
==========================================
  Files          21       21              
  Lines         598      598              
==========================================
- Hits          594      582      -12     
- Misses          4       16      +12     

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[codspeed-hq]

Merging this PR will degrade performance by 25.88%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

❌ 3 (👁 3) regressed benchmarks
✅ 229 untouched benchmarks

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
👁	test_stats_benchmark[scipy.sparse.csr_array-2d-ax1-float32-is_constant]	2.3 ms	2.8 ms	-15.9%
👁	test_stats_benchmark[scipy.sparse.csr_array-2d-ax1-float64-is_constant]	2.6 ms	3.7 ms	-28.95%
👁	test_stats_benchmark[scipy.sparse.csc_array-2d-ax0-int32-is_constant]	2.2 ms	3.3 ms	-31.84%

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_{Comparing grst-patch-1 (04d9a79) with main (c53c8ea)}