Avoid multiple DeferredRepositoryInitializationListener registrations in RepositoryConfigurationDelegate

[xeounxzxu]

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@mp911de

hello.

I changed the content for the following reasons.

issue: #3287

If you use two or more EnableJpaRepositories and use DEFERRED bootstrap mode, an error that the bean cannot be registered will occur.

Logic was added to check the presence of a bean. And we ran a repository check as a test case.

[xeounxzxu]

@odrotbohm Could you please check this PR?

[mp911de]

Thank you for your contribution. That's merged, polished, and backported now. Please make sure to use to use our formatter configuration on your next contribution to introduce less formatting-related changes. I fixed those.