Remove configureEnginePlugin from the exports

[davidjamesstone]

Proposed change

Remove the configureEnginePlugin from the plugin exports.
It's no longer needs to be exported and causes other modules to be loaded (like the localFormsService.js) when the main plugin is imported.

Azure DevOps work item:

Type of change

• Bug fix
• New feature
• Breaking change
• Misc. (documentation, build updates, etc)

Checklist

• You have executed this code locally and it performs as expected.
• You have added tests to verify your code works.
• You have added code comments and JSDoc, where appropriate.
• There is no commented-out code.
• You have added developer docs in README.md and docs/* (where appropriate, e.g. new features).
• The tests are passing (npm run test).
• The linting checks are passing (npm run lint).
• The code has been formatted (npm run format).

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[alexluckett]

Done already: https://github.com/DEFRA/forms-engine-plugin/blob/main/src/server/plugins/engine/index.ts