Update minute-volume.md

[JV0812]

Purpose of this pull request

This pull request is to add more info about the query as per the comments from Jeff in the ticket.

Select the type of change

• Minor Changes - Typos, formatting, slight revisions
• Update Content - Revisions, updating sections
• New Content - New features, sections, pages, tutorials
• Site and Tools - .clabot, version updates, maintenance, dependencies, new packages for the site (Docusaurus, Gatsby, React, etc.)

Ticket (if applicable)

Minute Volume Ingest Budget - Replace Example Query to Calculate Current Ingest Rates