Simplify "screenshot ready" logic in act-now-links-service and components / templates.

[mikelehen]

As discussed at standup, I think we could have two classes that we use in our components that asynchronously load data:

• act-now-data-loading - used initially before data is loaded / ready.
• act-now-data-loaded - used after data is rendered and it's safe to take a screenshot.

And the link service could wait until:

1. At least one instance of act-now-data-loaded exists on the page.
2. No instances of act-now-data-loading exists on the page.

Then you can just use our components in your share image, and it'll "just work" without any logic / mutation observers, etc...