[Backport 2.x] Replace bouncy castle blake2b

[terryquigleysas]

Description

Backport #4275 to 2.x

Issues Resolved

Resolves #4212

Testing

Tests confirm backwards compatibility

Check List

• New functionality includes testing
• New functionality has been documented
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 65.79%. Comparing base (d5e328d) to head (28cd030).

Additional details and impacted files

@@           Coverage Diff           @@
##              2.x    #4284   +/-   ##
=======================================
  Coverage   65.79%   65.79%           
=======================================
  Files         296      296           
  Lines       21260    21260           
  Branches     3471     3471           
=======================================
+ Hits        13988    13989    +1     
+ Misses       5529     5527    -2     
- Partials     1743     1744    +1     

Files	Coverage Δ
...opensearch/security/configuration/MaskedField.java	54.45% <100.00%> (ø)

... and 2 files with indirect coverage changes