fix amp-sidebar toolbar issue with chrome

[omar-toma]

closes #12205

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[omar-toma]

I signed it!

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CLAs look good, thanks!

[aghassemi]

Thanks for the fix @omar-a-toma
/to @camelburrito for review

[aghassemi]

@camelburrito Can this move to buildCallback?

[camelburrito]

No because at this point the toolbar had been built and this code attempts to inject it at the right place on the DOM when layout changes based on the viewport width + toolbar config

[aghassemi]

LGTM, @camelburrito any changes you like to this?

[camelburrito]

I think it i would be better to add one small test to check if we are waiting for onready