Stories: Scale to fill rendering + post-export overlays bug fixes

[bjtitus]

WordPress PR: wordpress-mobile/WordPress-iOS#16109

🐞 Text disappears when using OpenGL + scaleToFill

This was an alignment issue with text when using OpenGL + scaleToFill content mode.

Demo

Notice the disappearing text after the confirm button is pressed.

Before	After
RPReplay_Final1615954257.mp4	RPReplay_Final1615954109.mp4

We now check the player's content mode before adjusting the size of the drawing & movable canvas views. These views are already properly sized to match the full size of the editor so we don't need to change them any further.

kanvas-ios/Classes/Editor/EditorView.swift

Lines 123 to 127 in 6803838

	if playerView?.contentMode != .scaleToFill {
	// When scaling to fill we don't need to update these views as they are already sized correctly.
	drawingCanvasConstraints.update(with: rect)
	movableViewCanvasConstraints.update(with: rect)
	}

🐞 Overlays disappear after exposing

Overlays were lost after exporting media. Because the Prepublishing sheet can be dismissed in WP-iOS, this causes text to be lost if the user goes back.

Demo

Notice how the text label disappears after dismissing the Prepublishing Sheet.

Before	After
Vid.mov	RPReplay_Final1615955075.mp4

We are reusing a single instance of MovableViewCanvas and it is not re-added to the current editor after exporting. It probably makes more sense to serialize the instance and create a new one but that change is more than we want to make after a code freeze.

This addition reloads the editor after export is complete to ensure all archived data and views are present:

kanvas-ios/Classes/Editor/MultiEditor/MultiEditorViewController.swift

Lines 377 to 379 in 6803838

	if let selected = self?.selected {
	self?.loadEditor(for: selected)
	}

[danielebogo]