[TIMOB-16503] iOS: Allow toolbar to extend below statusbar

Fixes [TIMOB-16503](https://jira.appcelerator.org/browse/TIMOB-16503)

Test case is in [comments](https://jira.appcelerator.org/browse/TIMOB-16503?focusedCommentId=294681&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-294681)