Only setup express server when necessary in tests

[emmatown]

This is because setting up the express server is somewhat expensive but most tests don't need it. The documentation updates for this will be in a separate PR.

[changeset-bot]

🦋 Changeset detected

Latest commit: 77d7317

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 39 packages

Name	Type
@keystone-6/core	Major
@keystone-6/example-assets-local	Patch
@keystone-6/example-assets-s3	Patch
@keystone-6/example-auth	Patch
@keystone-6/example-app-basic	Patch
@keystone-6/example-blog	Patch
@keystone-6/example-custom-admin-ui-logo	Patch
@keystone-6/example-custom-admin-ui-navigation	Patch
@keystone-6/example-custom-admin-ui-pages	Patch
@keystone-6/example-custom-field-view	Patch
@keystone-6/example-custom-field	Patch
@keystone-6/example-with-custom-session-validation	Patch
@keystone-6/example-default-values	Patch
@keystone-6/example-document-field	Patch
@keystone-6/example-ecommerce	Patch
@keystone-6/example-embedded-nextjs	Patch
@keystone-6/example-extend-graphql-schema-graphql-ts	Patch
@keystone-6/example-extend-graphql-schema-nexus	Patch
@keystone-6/example-extend-graphql-schema	Patch
@keystone-6/example-extend-graphql-subscriptions	Patch
@keystone-6/example-graphql-api-endpoint	Patch
@keystone-6/example-json-field	Patch
@keystone-6/example-rest-api	Patch
@keystone-6/example-roles	Patch
@keystone-6/example-task-manager	Patch
@keystone-6/example-testing	Patch
@keystone-6/example-virtual-field	Patch
@keystone-6/example-with-auth	Patch
@keystone-6/auth	Major
@keystone-6/cloudinary	Major
@keystone-6/fields-document	Major
@keystone-6/session-store-redis	Major
@keystone-6/benchmarks-legacy	Patch
@keystone-6/test-projects-basic	Patch
@keystone-6/test-projects-crud-notifications	Patch
@keystone-6/test-projects-live-reloading	Patch
@keystone-6/sandbox	Patch
@keystone-6/generate-artifacts-for-projects	Patch
@keystone-6/website	Patch

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Name	Status	Preview	Updated
keystone-next-docs	✅ Ready (Inspect)	Visit Preview	Aug 31, 2022 at 4:44AM (UTC)

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Sandbox	Source
@keystone-6/sandbox	Configuration