Add test for calculateActiveValidatorsUpdate

[mitsuaki-u]

What was the problem?

This PR resolves #7971

How was it solved?

Added missing test to utils.spec.ts

How was it tested?

Added missing unit tests

[codecov]

Codecov Report

Merging #9170 (07e492f) into release/6.1.0 (dcb7d10) will increase coverage by 0.34%.
Report is 58 commits behind head on release/6.1.0.
The diff coverage is 95.45%.

Additional details and impacted files

@@                Coverage Diff                @@
##           release/6.1.0    #9170      +/-   ##
=================================================
+ Coverage          84.35%   84.69%   +0.34%     
=================================================
  Files                655      656       +1     
  Lines              24137    24122      -15     
  Branches            3506     3497       -9     
=================================================
+ Hits               20361    20431      +70     
+ Misses              3776     3691      -85     

Files	Coverage Δ
...der/src/bootstrapping/commands/generator/export.ts	91.30% <100.00%> (-1.29%)	⬇️
commander/src/bootstrapping/commands/hash-onion.ts	82.75% <100.00%> (-3.36%)	⬇️
...ommander/src/bootstrapping/commands/keys/create.ts	100.00% <100.00%> (ø)
...ommander/src/bootstrapping/commands/keys/export.ts	94.73% <100.00%> (-0.51%)	⬇️
...er/src/bootstrapping/commands/passphrase/create.ts	100.00% <100.00%> (ø)
...r/src/bootstrapping/commands/passphrase/encrypt.ts	100.00% <100.00%> (ø)
commander/src/utils/flags.ts	100.00% <ø> (ø)
commander/src/utils/output.ts	100.00% <100.00%> (ø)
commander/test/helpers/transactions.ts	96.42% <100.00%> (+0.42%)	⬆️
framework/src/engine/endpoint/chain.ts	98.42% <100.00%> (+55.90%)	⬆️
... and 8 more

... and 2 files with indirect coverage changes