Main editor: when setting or saving the height, look only at elements that...

Main editor: when setting or saving the height, look only at elements that have style="height:..." set. Reset a previously saved erroneous "ed_size" value (over 5000px) to the default height of 360px. Fixes #23042 for trunk.

git-svn-id: https://core.svn.wordpress.org/trunk@23302 1a063a9b-81f0-0310-95a4-ce76da25c4cd