Code Velocity dashboard lists closed PR as open

[damccorm]

#8430 is listed as a currently open PR in http://metrics.beam.apache.org/d/code_velocity/code-velocity?orgId=1 even though it has been merged.

cc: [~amyrvold]

Imported from Jira BEAM-8389. Original Jira may contain additional context.
Reported by: altay.