Fix contract deploy fee estimation error

[yknl]

This fixes the contract deploy fee estimation function. Previously this was causing makeSmartContractDeploy fail when not specifying a fee. Also turns off no-unnecessary-type-assertion eslint warning.

Type of Change

• [ ] New feature
• [x] Bug fix
• [ ] API reference/documentation update
• [ ] Other

Does this introduce a breaking change?

No

Are documentation updates required?

No

Checklist

• [x] Code is commented where needed
• [x] Unit test coverage for new or modified code paths
• [x] npm run test passes
• [x] Changelog is updated
• [x] Tag 1 of @yknl, @zone117x, @reedrosenbluth for review

[codecov[bot]]

Codecov Report

Merging #95 into master will not change coverage. The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master      #95   +/-   ##
=======================================
  Coverage   84.17%   84.17%           
=======================================
  Files          28       28           
  Lines        1820     1820           
  Branches      367      367           
=======================================
  Hits         1532     1532           
  Misses        286      286           
  Partials        2        2           

Impacted Files	Coverage Δ
src/builders.ts	76.14% <0.00%> (ø)

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