Bug in scrollToBottomAnimated

[IceFloe]

Hi @jessesquires, one small bug I have found in the scrollToBottomAnimated function, when we calculate maxHeightForVisibleMessage. We should also minus self.collectionView.contentInset.bottom.

Should be like this one

CGFloat maxHeightForVisibleMessage = CGRectGetHeight(self.collectionView.bounds) - self.collectionView.contentInset.top - self.collectionView.contentInset.bottom - CGRectGetHeight(self.inputToolbar.bounds);

In other way when we have keyboard opened and a big image come to us in chat it will not scroll to UICollectionViewScrollPositionBottom. What do you think, should I create pull request?

Second small bug in the

`- (void)viewWillLayoutSubviews
{
[super viewWillLayoutSubviews];

if (!self.inputToolbar.contentView.textView.isFirstResponder) {
    [self jsq_setToolbarBottomLayoutGuideConstant:self.bottomLayoutGuide.length];
}

}
This code will not work with .hidesBottomBarWhenPushed = true`
Effect will be like jumping toolbar after view did appear. I am not sure for now how to fix this, but I can try.

[jessesquires]

Thanks @IceFloe ! 😄

A pull request for the first issue would be great! 👍

The second bug was fixed in v7.3.1

[jessesquires]

Be sure to submit the fix to the release_7.3 branch 😊