manage parent for RCE in discussion replies
manage parent for RCE in discussion replies

so that it doesn't eat the rest of the form; e.g. the post reply button

test-plan:
 - enable all remote RCE feature flags
 - go to an existing discussion
 - click to reply
 - RCE should show up, and so should the rest of the reply form

Change-Id: I72e311e04038b7275f715395e1f8d1648527faa2
Reviewed-on: https://gerrit.instructure.com/76016
Reviewed-by: Brent Burgoyne <bccf16d7abdd2611580b1cd7d7a6fcc150d619da@instructure.com>
Tested-by: Jenkins
Product-Review: Ethan Vizitei <73eeb0b2f65d05a906adf3b21ee1f9f5a2aa3c1c@instructure.com>
QA-Review: Ethan Vizitei <73eeb0b2f65d05a906adf3b21ee1f9f5a2aa3c1c@instructure.com>

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