[infra] Remove alert for skia-i-rpi*
[infra] Remove alert for skia-i-rpi*

We have no more internal RPIs.

Change-Id: I4993c062af03802b9b6acb02fe5e824733cf835c
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/453016
Bot-Commit: Rubber Stamper <d516c4cc2192058ab8dae3d306acbdaf2ce6574f@appspot.gserviceaccount.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot