Do not disable scrollZoom scroll{Width,Height} > client{Width,Height}

[etpinard]

fixes#2371 and #3337 by including a commit from @marfoldi's #3085.

Removing the scroll{Width,Height} > client{Width,Height} early return fixes two bugs:

• it fixesresponsive: true breaks scrollZoom: true #3337 where {responsive: true, scrollZoom: true} + graph div height vh units doesn't work, as in that scenario gd.client{Width,Height} is 0 leading to an early return.
• it fixesscrollZoom no longer works when page is scrollable #2371 where we get an early return when page is scrollable. See #2371: Not disabling scrollZoom when page (plot) has scroll bar #3085 (review) for more details.

There are probably other ways to fix these bugs, but that scroll{Width,Height} > client{Width,Height} early return feels out-of-place. It's probably a relic from the workspace days, where we set scrollZoom:true, but wanted some extra do-not-scroll logic. As scroll zoom is disable by default for cartesian subplots, I don't think overriding a scrollZoom: true user config is a good idea.

I hope @plotly/plotly_js agrees. If so, I'll add a few tests.

[etpinard]

@antoinerg would you mind taking a look at this one at some point this week?

[etpinard]

Oh wait. I still have to add a few tests for this one.

Asking for @alexcjohnson 's opinion on this potentially-controversial patch.

[alexcjohnson]

Agreed. Explicit is better than implicit.

[etpinard]

Oh wait. I still have to add a few tests for this one.

Done in 3ee0798 and 09e0a5d

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@antoinerg I know you're busy, but would you mind taking a 👁️ at this PR at some point this week (should be quick 😉 )

[antoinerg]

I am not sure what this early return was meant to achieve but I guess it's OK to 🔪 considering it doesn't have any associated tests...

[antoinerg]

Thank you for the fix @etpinard! It seems to work well: https://codepen.io/anon/pen/roRdmB

If the removed code really is a relic, then 💃