SpringBoot fix: NPE with Gradle plugin's BuildInfo#coerceToStringValues

fix bug: https://github.com/spring-projects/spring-boot/issues/30654

Comment From: wilkinsona

Thanks for the PR, @pruidong. Unfortunately, as described in https://github.com/spring-projects/spring-boot/issues/30654#issuecomment-1099443180, I don't think this is the right way to fix the problem. Thanks anyway.