With `plnkrs`, we used to choose a different plnkr mode (normal vs
embedded) based on the size of the screen. This affected the layout of
the plnkr page ("embedded" plnkr mode was usable on small screens, while
"normal" mode wasn't). This is not to be confused with the live-example
mode we use today to determine whether the live-example should be a link
(that open StackBlitz on a new page) or embedded into the document
(using an iframe).
Since we no longer need to change the live-example URL based on the
screen size, there is no need to listen for rezise events on Window. The
necessary properties can be computed once and certain variables are
obsolete.
PR Close#23960
Previously, it was possible to set the live-example title as content in
the `<live-example>` element. This relied on our custom loader
functionality that extracted the content from the DOM element before
passing it to the Angular compiler and stored it on a property for later
retrieval.
Since we switched to custom elements (and got rid of the custom loader),
the property is no longer populated with the contents. As a result, many
live examples show the default title ("live example") instead of the one
specified as content.
This commit fixes it by projecting the content into an invisible node
for later retrieval (similar to what we do in other components, such as
the `CodeExampleComponent`).
PR Close#23960
