Popover – RawButton wraps Trigger when not needed

# Bug Report

## Expected behavior
When a `` is used with the ``, no `` should wrap it. However, sometimes if an `` or other non-interactive element is used for the trigger, it may still be convenient.

## Current behavior
When the `` is given a `node` as `children`, it will always wrap it with a ``. It's necessary to provide a `function` as `children` to avoid this behaviour.

## Examples
``
https://github.com/acl-services/paprika/pull/113#discussion_r302289468
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