Tools: Revert "feat: add support to display mnemonic discreetly for algokey generate"

[onetechnical]

Summary

Reverts #5886

As part of a review of our external dependencies (in the wake of the xz incident), we decided the sensitivity of this data was not worth the risk inherent in post-processing it with this external library.

Testing

Verify algokey behavior works as expected.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.02%. Comparing base (0e7087b) to head (48497a3).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5974      +/-   ##
==========================================
+ Coverage   55.73%   56.02%   +0.29%     
==========================================
  Files         490      481       -9     
  Lines       68125    67646     -479     
==========================================
- Hits        37967    37901      -66     
+ Misses      27586    27182     -404     
+ Partials     2572     2563       -9     

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[johnalanwoods]

Agreed. It's too sensitive.