Remove volume_device events. They are now just device events.

[matthewscherer]

Change Summary

Remove volume_device events. These were already replaced with device events.

Sample values

Release Target

Q/A

For mapping changes:

• I ran make after making the schema changes, and committed all changes
• If these field(s) are "exception"-able, I made a companion PR to Kibana adding it (see Readme)
• If this is a metadata change, I also updated both transform destination schemas to match

For Transform changes:

• The new transform successfully starts in Kibana
• The corresponding transform destination schema was updated if necessary