Added bundle for djblets-integrations for running JavaScript unit tests.
Added bundle for djblets-integrations for running JavaScript unit tests.

When the JavaScript unit tests were run, the djblets-integration bundle
is never loaded. This leads to the djblets integration tests failing,
because they require that bundle in order to run correctly. This change
simply loads that bundle before unit tests are run.

Testing Done:
I tested locally by hitting http://localhost:8080/js-tests/

Reviewed at https://reviews.reviewboard.org/r/10688/

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