CloudMonitoring: Fix crash when inspecting data for MQL queries (#63747)
CloudMonitoring: Fix missing Field name
This happened for MQL queries that used an [aggregate function][1], e.g.
`sum`.
[1]: https://cloud.google.com/monitoring/mql/reference#aggr-function-group
(cherry picked from commit 3672e44c1c)
Co-authored-by: Adam Simpson <adam@adamsimpson.net>