Disable percy finalize step

[etpinard]

until #177 is resolved.

---

First step towards making the next Dash.jl release (ref #175 (comment))

[etpinard]

Ok, looks like Percy is still invoked from

Dash.jl/.circleci/config.yml

Line 43 in f0606e0

pytest --headless --nopercyfinalize --junitxml=test-reports/dashjl.xml --percy-assets=test/assets/ test/integration/

and is currently hanging.

I think we'll just have to disable the whole workflow until #177 is addressed.

Closing. I'll open a new PR that disables the workflow.