Include original call-site in QueryMonitor

[lfittl]

The next release is going to add a query monitor feature that hints you at queries that might be missing the tenant_id filter because there is no wrapping MultiTenant.with(..) block:

https://github.com/citusdata/activerecord-multi-tenant/commit/b048e43b07795d8643d6d65a7063986e6b2dadf2

It might be worthwhile to include the original call site, as proposed for Rails' own statement logging here: https://github.com/rails/rails/pull/26815