Restore integer representation of nproc value

[knoepfel]

Also trims newline from the returned value of nproc (or its equivalent)

This PR addresses the failure:

43: Error retrieving parameter 'expected_parallelism':                                                                              
43: not a number [boost.json:26 at /Users/kyleknoepfel/work/phlex-devel/local/.spack-env/._view/dlpaqk7urgh5dyallqyurp23btjxmoxo/include/boost/json/value.hpp:2370:30 in function 'typename std::enable_if<std::is_arithmetic<T>::value && !std::is_same<T, bool>::value
, T>::type boost::json::value::to_number(system::error_code &) const [T = unsigned long]']

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

❌ Your project status has failed because the head coverage (75.24%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.

@@            Coverage Diff             @@
##             main     #283      +/-   ##
==========================================
+ Coverage   75.20%   75.24%   +0.03%     
==========================================
  Files         124      124              
  Lines        2916     2916              
  Branches      513      513              
==========================================
+ Hits         2193     2194       +1     
  Misses        503      503              
+ Partials      220      219       -1     

Flag	Coverage Δ
unittests	75.24% <ø> (+0.03%)	⬆️

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see 1 file with indirect coverage changes

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[wlav]

lgtm.

Edit: I'll add that I also tried the commands and they work. :)

[knoepfel]

lgtm.

Edit: I'll add that I also tried the commands and they work. :)

Thanks @wlav