Getting 400 error on creating page & source editor requests

Issue Summary

This is reproducible on Data Center: (yes)

If the page contains one of the following characters sets in the content the saving process gets a HTTP 400 message.

../ 
..\ 
…/ 
…\

Steps to Reproduce

Apart from what's already fixed in CONFSERVER-93655, we have identified a few other requests:

• Create a page and add ../ directly, click close button
• Add ../ in a page and click <> to open source editor, source editor shows an error when attempting to get storage format.