Simplify the reference to RABBITMQ_RUN in bazel in integration tests (backport #7989) (backport #7992)

[mergify]

This is an automatic backport of pull request #7992 done by Mergify.
Cherry-pick of 330aa8a has failed:

On branch mergify/bp/v3.11.x/pr-7992
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	both modified:   rabbitmq.bzl

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