security-command-center: samples contain many Spotbugs errors

## In which file did you encounter the issue?

https://github.com/GoogleCloudPlatform/java-docs-samples/tree/main/security-command-center/snippets

## Did you change the file? If so, how?

no

## Describe the issue

[`SAMPLE_FORMAT.md`](https://github.com/GoogleCloudPlatform/java-docs-samples/blob/main/SAMPLE_FORMAT.md) says the following:

> To run the Checkstyle, ErrorProne and SpotBugs plugins on an existing sample, run
>
> ```
> mvn clean verify -DskipTests -P lint
> ```

However, when I run that command in the `security-command-center/snippets` directory, it fails with 67 "bugs" (errors, really). I expected everything to pass at `HEAD`.

I didn't check any other directories, so this issue might exist elsewhere.