[1.6.x] Revert "Fixed #20296 -- Allowed SafeData and EscapeData to be lazy"

This reverts commit 2ee447fb5f8974b432d3dd421af9a242215aea44.

That commit introduced a regression (#21882) and didn't really
do what it was supposed to: while it did delay the evaluation
of lazy objects passed to mark_safe(), they weren't actually
marked as such so they could end up being escaped twice.

Refs #21882.

Backport of a878bf9b093bf15d751b070d132fec52a7523a47 from master.
[1.6.x] Added previous commit to 1.6.2 release notes.

Backport of 2dd88f0687c2bc9c457816a011bf5e46f6bf84ad from master.