Use Numpy rng in TDEM tests

[santisoler]

Summary

Replace the usage of the deprecated functions in numpy.random module for the Numpy's random number generator class and its methods, in most of the TDEM tests.

PR Checklist

• If this is a work in progress PR, set as a Draft PR
• Linted my code according to the style guides.
• Added tests to verify changes to the code.
• Added necessary documentation to any new functions/classes following the
  expect style.
• Marked as ready for review (if this is was a draft PR), and converted
  to a Pull Request
• Tagged @simpeg/simpeg-developers when ready for review.

Reference issue

Part of the solution to #1289

This PR might be related to #1233

What does this implement/fix?

Additional information

TODO:

• Double check if this can tackle BUG: Failing TDEM derivative tests #1233

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.34%. Comparing base (c31da25) to head (d33db3f).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1452   +/-   ##
=======================================
  Coverage   82.34%   82.34%           
=======================================
  Files         171      171           
  Lines       26027    26027           
=======================================
  Hits        21431    21431           
  Misses       4596     4596           

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