Fix: Important dates checkbox moves the footer in Assignments
Fix: Important dates checkbox moves the footer in Assignments

This PS adds the inline prop to the Important Dates Checkbox, this
will prevent the layout be affected by the component height changes

fixes LS-2399
flag = important_dates

Test plan:
1.With the important dates feature enabled, as a teacher go to any
course assignments page
2. Create or edit an assignment
3. Go to the “Mark as important date...” checkbox, check it and then
uncheck it
4. Expect the footer doesn't move

Change-Id: Ifa07e36f9f02cf238e5b6cf04f7f2d590fca9c11
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/269928
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Robin Kuss <0b206b54367b2de0334896ea45826f0e3194bd35@instructure.com>
QA-Review: Robin Kuss <0b206b54367b2de0334896ea45826f0e3194bd35@instructure.com>
Product-Review: Jonathan Guardado <94d0a13686225e6d8af5347ed17f9cc0c2643995@instructure.com>

sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms