Media Picker: replicate behavior of making a local copy for remote media for Stories

[mzorz]

After the implementation of this PR #13548, we changed the behavior for the media picker for Stories when the user selects a media item which belongs to the site's Media section. Given these items are represented with remote URLs (i.e. https://) we need to first download a local copy in order for things to behave properly and smoothly in the Story composer while the user makes edits to their slides.

This behavior should be replicated in the new consolidated Media Picker once we move Stories to use the new media picker as well.

cc @aforcier

[stale]

This issue has been marked as stale because:

• It has been inactive for the past year.
• It isn't in a project or a milestone.
• It hasn’t been labeled [Pri] Blocker, [Pri] High, or good first issue.

Please comment with an update if you believe this issue is still valid or if it can be closed. This issue will also be reviewed for validity and priority during regularly scheduled triage sessions.

[SiobhyB]

Stories have been deprecated as of 24.1 (released to users yesterday), so I'll go ahead to close this issue.