spec: don't use an undefined path for optimized js
spec: don't use an undefined path for optimized js

refs CNVS-25916

this was producing an undefined path for jenkins nodes
on selenium runs, we can go with the local assets for them.

Change-Id: Ic5009b001bb369d65ab2dbc6dce360b38e93e437
Reviewed-on: https://gerrit.instructure.com/69359
Reviewed-by: Jacob Fugal <f862f167b85d41b225785c70d70808bc7337c1fe@instructure.com>
Reviewed-by: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
Tested-by: Jenkins
Product-Review: Ethan Vizitei <73eeb0b2f65d05a906adf3b21ee1f9f5a2aa3c1c@instructure.com>
QA-Review: Ethan Vizitei <73eeb0b2f65d05a906adf3b21ee1f9f5a2aa3c1c@instructure.com>

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