Fix comment regarding left/right side in BouncerContent

The comment for the second Box inside the Row in SplitLayout incorrectly states it's on the "Right side (in right-to-left locales)". In RTL layouts, a Row places its second child on the left. The comment should say "Right side (in left-to-right locales)" to be consistent with the comment for the first Box and accurately describe the visual layout in LTR.

Bug: None
Flag: EXEMPT - comment only fix
Test: None - comment only fix

Change-Id: If047781693e19a4dd6376b5f9891c896350bf256