spec: fix intermittent dashboards_spec.rb failure
spec: fix intermittent dashboards_spec.rb failure

refs DE-109

flag = none

Change-Id: Idb030f04169f12bec60222390122df8998e84d96
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/241966
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: James Butters <4c5a489c9bb72d41f20b3b22aaf4c9b864e32f20@instructure.com>
QA-Review: Aaron Ogata <11ccf682c06d1508642f943a3962a1c3d00b8e44@instructure.com>
Product-Review: Aaron Ogata <11ccf682c06d1508642f943a3962a1c3d00b8e44@instructure.com>

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