Fix (Whiteboards): An attempt to fix most of the remaining issues

[sprocketc]

• Check if snapshot pages exist (resolves Whiteboard crash in latest nightly #8886)
• Fix breadcrumbs without label (resolves Bugs in display of whiteboard #7087 - not a whiteboards specific issue)
• Maintain original page name when we create a new page within a whiteboard (resolves Changing the name of a page created from whiteboard makes the whiteboard crash #7811)
• Allow scrolling on tools (resolves [Whiteboard] Toolbar in whiteboard can't be scrolled when it is overflowed #8364). This might not be the perfect solution, but it allows access to the tools that overflow the screen.
• This PR also reverts cb2c1f1 that seems to be causing focus issues on inputs. If you click to edit a page title and then click again somewhere in the middle of the input, the focus will be lost. Also, if you try to create a text element on whiteboards, you won't be able to type.

[tiensonqin]

Awesome PR! Worked as described! 🚢

[mistune]

Will whiteboards be out in the next release after this fix? :)

[sprocketc]

@ZeroCommits Sorry for the late reply. Yes, whiteboards are out since 0.9.0.