Jetstream fails when a metric and a segment share a name

[ncalexan]

The issue is about "duplicated column names", although I can't provide the exact stack trace easily right now. I think that this is inherent in the design, which doesn't namespace segments and metrics internally.

┆Issue is synchronized with this Jira Task

[mikewilli]

Yea it doesn't surprise me that this wasn't accounted for in the design. If it's straightforward, we should definitely fix this, but if that's going to be more complicated than it's worth, at the very least we should add a CI check to warn people when there are conflicts.