Fix line delimited JSON response

For GET /events, line delimit JSON.
Fixes #7047

Signed-off-by: Jessica Frazelle <jfrazelle@users.noreply.github.com>

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jfrazelle@users.noreply.github.com> (github: )
Merge pull request #7886 from jfrazelle/7047-json-line-delim

Fix line delimited JSON response