Fixed: composite content-view definiion was failing due to timing issue

Promotion is working fine when we promote a content-view. However when we promote composite content-view, the fn `changeset/promote-or-delete` actually skips to click the review-promotion step and directly tries to promote the changeset so selenium throws this error:
ERROR: Element //div[@id='promote_changeset' and not(contains(@class,'disabled'))] not found

Added a unwanted sleep to fix it. Later, deletion changeset is throwing undefined error (katello bug) so blocked the test with bz.