SpringBoot Buildsrc fails to resolve Spring Framework snapshots

I believe this is a "regression" introduced by #35224. When moving to Spring Framework snapshots, the build fails as follows:

* What went wrong:
Execution failed for task ':buildSrc:compileJava'.
> Could not resolve all files for configuration ':buildSrc:compileClasspath'.
   > Could not find org.springframework:spring-framework-bom:5.3.28-SNAPSHOT.
     Searched in the following locations:
       - https://repo.maven.apache.org/maven2/org/springframework/spring-framework-bom/5.3.28-SNAPSHOT/maven-metadata.xml
       - https://repo.maven.apache.org/maven2/org/springframework/spring-framework-bom/5.3.28-SNAPSHOT/spring-framework-bom-5.3.28-SNAPSHOT.pom
       - https://plugins.gradle.org/m2/org/springframework/spring-framework-bom/5.3.28-SNAPSHOT/maven-metadata.xml
       - https://plugins.gradle.org/m2/org/springframework/spring-framework-bom/5.3.28-SNAPSHOT/spring-framework-bom-5.3.28-SNAPSHOT.pom
     Required by:
         project :buildSrc
   > Could not find org.springframework:spring-context:.
     Required by:
         project :buildSrc
   > Could not find org.springframework:spring-core:.
     Required by:
         project :buildSrc
   > Could not find org.springframework:spring-web:.
     Required by:
         project :buildSrc