DRIVERS-2407 update expected error in fle2-InsertFind-Unindexed

[kevinAlbs]

Summary

• Update expected error in fle2-InsertFind-Unindexed.

Background & Motivation

The expected error message changed recently in https://github.com/10gen/mongo-enterprise-modules/commit/212b584d4f7a44bed41c826a180a4aff00923d7a#diff-5f12b55e8d5c52c2f62853ec595dc2c1e2e5cb4fdbf7a32739a8e3acb3c6f818 Driver tests against "latest" will start failing.

Before the message was "cannot query non-indexed fields with the randomized encryption algorithm". Now it is "can only execute encrypted equality queries with an encrypted equality index".

Please complete the following before merging:

• Bump spec version and last modified date.
• Update changelog.
• Make sure there are generated JSON files from the YAML test files.
• Test changes in at least one language driver. Tested in Go
• Test these changes against all server versions and topologies (including standalone, replica set, sharded clusters, and serverless).