HttpHealthIndicator is marked as a scoped provider, causing the server to not start up with the usage of the HttpHealthCheckStrategy

[sidings]

Describe the bug
The HttpHealthCheckStrategy uses the HttpHealthIndicator provided by the @nestjs/terminus package. When using the HttpHealthCheckStrategy as one of the application health checks, the server fails to start up and throws an error:

InvalidClassScopeException [Error]: HttpHealthIndicator is marked as a scoped provider. Request and transient-scoped providers can't be used in combination with "get()" method. Please, use "resolve()" instead.

This wasn't happening when I was using Vendure version 1.9.5, but is now happening when I'm on version 2.0.4.

To Reproduce
Steps to reproduce the behavior:

1. Add the following to the vendure-config.ts file.

   systemOptions: {
   healthChecks: [
    new HttpHealthCheckStrategy({
      key: 'admin-ui-probe',
      url: <URL>,
    }),
   ],
   

2. Start the server.
3. See error in the logs.

Expected behavior
I expect the server to start up properly and the health check to be initialized.

Environment (please complete the following information):

• @vendure/core version: 2.0.4
• Nodejs version: 18
• Database (mysql/postgres etc): Postgres

Additional context
Add any other context about the problem here.

[michaelbromley]

OK I found a couple of issues going on here:

1. First of all, we were using the injector.get(HttpHealthIndicator) method but NestJS requires the use of injector.resolve(HttpHealthIndicator) in this case. That was probably an API change that I didn't notice in one of the updates.
2. But resolving that issue exposed a deeper issue: due to internal changes in some earlier NestJS versions, the HttpHealthIndicator depends on the @nestjs/axios and axios packages being installed, and the HttpModule being imported into the core.

Since I don't really want to add 2 new dependencies for this single case (which is probably quite rarely used), I will create a custom health indicator which has no new dependencies for the next patch version.