[ios] Scalebar position and size is incorrect

[julianrex]

#13556 introduced new ornament placement, which unfortunately has affected the position and size of the MGLScaleBar.

#13870 proposes reverting the PR until this can be fixed, but this ticket should be used to document the specific issues.

Zooming in/out changes the position and width of the scale bar, as does rotating the device.

Looking in the view debugger you can see width and height constraints, but none for the position (it looks like size is handled by the "intrinsic content size" - so perhaps this is changing?). Looking in the debugger where the constraints are installed - you do see them listed in the parent view.

/cc @chloekraw @chriswu42

[lloydsheng]

@julianrex Thanks for investigating the issue. I found it was caused by this commit 2f2886c#diff-20502b6bc02986a4398d0da84b2d4b94L915 . I removed width and height constraints by mistake. The issue affacts iOS 11+ but I just tested iOS9.
I'll fix the issue on branch lloyd-ui-position and have a full manual test like this #13556 (comment) before create a PR.

/cc @fabian-guerra @chriswu42

[julianrex]

Thanks for looking at this so quickly @lloydsheng! We'll plan to review and merge so that it hits the next beta!