fix(typescript): import from 'grpc' -> '@grpc/grpc-js'

[AVaksman]

Fixes #<issue_number_goes_here> (it's a good idea to open an issue first for discussion)

• Tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

[codecov]

Codecov Report

Merging #446 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #446   +/-   ##
=======================================
  Coverage   98.05%   98.05%           
=======================================
  Files           5        5           
  Lines         617      617           
  Branches      145      145           
=======================================
  Hits          605      605           
  Partials       12       12

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[tseaver]

@AVaksman the yoshi team is overbroad for review here: it picks up developers across all languages.

[AVaksman]

@AVaksman the yoshi team is overbroad for review here: it picks up developers across all languages.

@tseaver understood
meant to select googleapis/yoshi-nodejs