fix: CallRecord tersifies without undefined properties.

[unional]

Making it more terse to read.

[coveralls]

Coverage remained the same at 100.0% when pulling 5b2b4eb on up-tersify into 9149cb5 on master.

[codecov]

Codecov Report

Merging #29 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master    #29   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           9      9           
  Lines         154    154           
  Branches       32     32           
=====================================
  Hits          154    154

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