storybook: Addon-docs: Docs mode shouldn't render "Canvas" & "Docs" tabs

Describe the bug

In 5.2 when Storybook is compile in --docs mode the “Canvas” & “Docs” tabs are not rendered, which is great.

In 5.3.6 it doesn’t seems to be the case anymore:

To Reproduce Steps to reproduce the behavior:

1. Start storybook with --docs

Expected behavior

“Canvas” & “Docs” tabs are not rendered.

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Code snippets If applicable, add code samples to help explain your problem.

System:

Environment Info:

System: OS: Windows 10 10.0.17763 CPU: (8) x64 Intel® Core™ i7-6700HQ CPU @ 2.60GHz Binaries: Node: 12.5.0 - C:\Program Files\nodejs\node.EXE Yarn: 1.21.1 - C:\Dev\20_gsoft\sg-orbit\node_modules.bin\yarn.CMD npm: 6.9.0 - C:\Program Files\nodejs\npm.CMD Browsers: Edge: 44.17763.831.0

Additional context Add any other context about the problem here.