Prune samples tests

[mbhave]

A few of the samples tests don't run on CI but still take up time. We can most likely delete them as there are other tests using TestContainers that cover that:

• SampleElasticsearchApplicationTests
• SampleRedisApplicationTests
• SampleSolrApplicationTests
• SampleCouchbaseApplicationTests
• SampleNeo4jApplicationTests

There are a few others that don't seem to test the sample they're part of. For example, SampleDevToolsApplicationIntegrationTests passes even if devtools is not on the classpath. Since we have other integration tests for DevTools, these can probably go. SampleAopApplicationTests also doesn't test the relevant aop parts.

[wilkinsona]

I think we should use this issue and #6370 to review all of our samples, decide what they should be used for, and update and name them accordingly.

[scottfrederick]

The data-related smoke tests that require a server will be removed in #30875. We will leave this issue open to do the suggested additional review.

[wilkinsona]

With the modularity, there's some more benefit to having samples/smoke tests that pull everything together and test it in one application-like place. I think we can afford to leave things as they are.