In incremental layout, changes to the `quotes` attribute of a
pseudo-elment can cause the content of the pseudo-element to change so
should cause a box rebuild. This change does that, hopefully fixing
flaky tests.
Testing: This doesn't have any test changes, but should fix the test
situation described in #40419.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>