Option to load saved object state instead of current object state when sharing

[jimmyjones2]

When sharing or using an embedding link it contains the full dashboard config. Therefore if you share the link, or embed it somewhere, then update the dashboard, you'll still get the old one, which in some (majority?) of cases isn't desirable. I've worked around this by removing the _a URL parameter, which seems to cause the latest version of the dashboard to be loaded, but would be great to have a checkbox when generating the sharing/embed URL to do this automatically.

[tbragin]

@cjcenizal @BigFunger Also a pain point for shortened links, which take into account the whole state. Should the default for sharing to be not to include the full state, so that bookmarks and shared links do not get stale?

[spalger]

Closed by #8172