fix(samples): end stream before destroying it

[Wirnex]

I've been getting this error until I put call of end() for the stream before destroying it.
API request error 14 UNAVAILABLE: 408:Request Timeout

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Fixes #<issue_number_goes_here> 🦕

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[codecov]

Codecov Report

Merging #611 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #611   +/-   ##
=======================================
  Coverage   94.90%   94.90%           
=======================================
  Files           9        9           
  Lines        1530     1530           
  Branches       90       90           
=======================================
  Hits         1452     1452           
  Misses         76       76           
  Partials        2        2           

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[Wirnex]

@googlebot I signed it!

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CLAs look good, thanks!

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[bcoe]

@Wirnex It's not immediately apparent to me why this would help suppress that error. @alexander-fenster can you shine any light on what might be happening here?

[alexander-fenster]

Let me see if I can reproduce the failure.

[alexander-fenster]

Thanks @Wirnex, and sorry for delay!