Revert "Added a little hack for WYMeditor image dialog paging."

This reverts commit 0ca6dbaeaf6566ac4991323ac4a1b613fd6b7fed.

The commit was introduced because of issue refinery/refinerycms#2639

However, I don't believe it is needed.  Instead this alternate fix should do the job:  https://github.com/asgeo1/refinerycms-wymeditor/commit/a2106da63deae94e510ea030e258d87a724b0c4b

Which was submitted in a PR for this issue: parndt/refinerycms-wymeditor#16

You just need to make sure you're using the latest version of `refinerycms-wymeditor` gem.