Project integrations inherit instance level settings by default

We are implementing &2430 to transition Service Templates to an inheritable instance-level configuration as part of the mass-integration epic.

This is an iteration that will enable us to eventually accomplish the next goal of group-level integration settings from which projects can inherit by default.

#196525 (closed) defines the UI work for moving Service Templates into Integration settings in the Admin Area. When this UI change goes live, the change from service templates to a default inheritance should also go live.

Current Behavior (Service Template): If a service template is enabled, a project-specific service record is copied from the template. Modifying the service template does not modify the service/integration settings for the new project.

Desired Behavior (Instance-Level Integration): When the instance-level integration is enabled, we do not create a new service record when a new project is created, and the project inherits the instance-level settings. A user can deactivate the integration at the project level or override the inheritance by entering custom values. This triggers the creation of a project-specific service record to override the instance-level settings.

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