[BEAM-2509] Enable grpc controller in fn_api_runner

[vikkyrk]

Be sure to do all of the following to help us incorporate your contribution
quickly and easily:

• Make sure the PR title is formatted like:
  [BEAM-<Jira issue #>] Description of pull request
• Make sure tests pass via mvn clean verify.
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[coveralls]

Coverage increased (+0.007%) to 70.896% when pulling 556d291 on vikkyrk:fn_api_runner_test into 95e6bbe on apache:master.

[vikkyrk]

R: @robertwb
CC: @lukecwik @aaltay

[coveralls]

Coverage remained the same at 70.875% when pulling 60063c2 on vikkyrk:fn_api_runner_test into 8036001 on apache:master.

[robertwb]

LGTM, thanks.