Use std::size_t for Array

[sethrj]

Using celeritas::size_type (which is 32-bit when CUDA is enabled) causes weird inconsistencies with Span. We do not want to change Span to use size_type, because Span<byte> underpins our device allocator. This should have no adverse effects and should improve compatibility with other libraries.

[codecov]

Codecov Report

❌ Patch coverage is 95.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 87.19%. Comparing base (8874128) to head (9cd2114).
⚠️ Report is 2 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/orange/MatrixUtils.cc	91.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2341      +/-   ##
===========================================
- Coverage    87.20%   87.19%   -0.02%     
===========================================
  Files         1373     1373              
  Lines        43581    43581              
  Branches     13785    13785              
===========================================
- Hits         38005    37999       -6     
- Misses        4535     4537       +2     
- Partials      1041     1045       +4     

Files with missing lines	Coverage Δ
src/corecel/cont/Array.hh	100.00% <ø> (ø)
src/corecel/cont/ArrayIO.json.hh	91.66% <ø> (ø)
src/corecel/cont/Span.hh	100.00% <ø> (ø)
src/corecel/data/HyperslabIndexer.hh	100.00% <ø> (ø)
src/corecel/io/Repr.hh	52.43% <ø> (ø)
src/corecel/math/ArrayOperators.hh	100.00% <ø> (ø)
src/corecel/math/ArrayQuantity.hh	96.77% <100.00%> (ø)
src/corecel/math/ArraySoftUnit.hh	100.00% <ø> (ø)
src/corecel/math/ArrayUtils.hh	100.00% <ø> (ø)
src/corecel/math/PolyEvaluator.hh	100.00% <ø> (ø)
... and 8 more

... and 5 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

Test summary

 5 960 files   9 617 suites   19m 37s ⏱️
 2 242 tests  2 201 ✅  41 💤 0 ❌
33 498 runs  33 371 ✅ 127 💤 0 ❌

Results for commit 9cd2114.

♻️ This comment has been updated with latest results.

[pcanal]

Thanks.