Technically, splash water bottles damages enderman AND blazes by 1 heart but it doesn't seem to happen in the specified version. This is a bug that seems to be fixed in the past but returned.
MCPE-45834
Splash Water Bottles not damaging blazes.
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As seen in the clip I attached, bottles thrown by both players and dispensers do not work. Along with this, this is not a feature request, as seen here: