Button attribute values have trailing space

Problem/Motivation

When adding multiple button attributes, the attribute values have a trailing space like this:
my-attribute="value "

This only happens if there is more than one attribute.

Also I was only noticing this on the production server not on my local development server, using the exact same views config. So Im guessing it has to do with the way my two environments handle line breaks.

Proposed resolution

add a trim() around the attribute value when rendering the button.

I will provide a patch.