Blog post author list has an extra space before commas

Noticed this in a recent 3-author blog post:

https://beam.apache.org/blog/kafka-to-pubsub-example/

"Jan 15, 2021 • Artur Khanin , Ilya Kozyrev , & Alex Kosolapov"

Note the space between each author and the following comma

Imported from Jira [BEAM-11745](https://issues.apache.org/jira/browse/BEAM-11745). Original Jira may contain additional context.
Reported by: bhulette.

Start with the linked blog post at beam.apache.org/blog/kafka-to-pubsub-example/ and trace the template or entry point that renders its author list. Confirm the extra spaces before commas in the three-author display, then verify that the rendered author separators have no preceding spaces.

Written by the indexing model from the issue text.