Research reasons why exports with metrics are hanging & timing out

[kawcl]

Notes:

• Time outs occur after exactly 90 seconds.
• Browser waits for the query to finish before displaying toast message. Should we continue this behavior?
• Latency was observed for all users when the export was being processed.

[amurphy-cl]

Will not need a hotfix for this - will change GET to POST, or not await response from endpoint.