fix: supply calculation

[spkjp]

Proposed changes

The supply calculation assumed the milestone would never change, which is not the case.

This PR adds a new helper to calculate the correct supply at the given height
by taking all the milestones up to the height into account.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (improve a current implementation without adding a new feature or fixing a bug)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Build (changes that affect the build system)
• Docs (documentation only changes)
• Test (adding missing tests or fixing existing tests)
• Other... Please describe:

Checklist

• I have read the CONTRIBUTING documentation
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[codecov-io]

Codecov Report

Merging #1640 into develop will increase coverage by 0.18%.
The diff coverage is 92.85%.

@@             Coverage Diff             @@
##           develop    #1640      +/-   ##
===========================================
+ Coverage    74.74%   74.92%   +0.18%     
===========================================
  Files          439      440       +1     
  Lines         7896     7917      +21     
  Branches      1039     1044       +5     
===========================================
+ Hits          5902     5932      +30     
+ Misses        1771     1764       -7     
+ Partials       223      221       -2

Impacted Files	Coverage Δ
packages/core-vote-report/lib/handler.js	0% <0%> (ø)	⬆️
...ackages/core-api/lib/versions/1/handlers/blocks.js	88.57% <100%> (-0.91%)	⬇️
packages/core-utils/lib/supply-calculator.js	100% <100%> (ø)
...p2p/lib/server/versions/internal/handlers/utils.js	86.66% <0%> (+6.66%)	⬆️
packages/core-forger/lib/manager.js	78.64% <0%> (+6.79%)	⬆️

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