Enhancement: Check if the zip artifact contains a .pom file

[romtsn]

In the build.yml we have a check that the cli is bundled within the final zip artifact - we could expand it and also check for all files required for publishing (.jar, sources.jar, javadoc.jar and .pom files). This would enable us fail early when calling craft prepare

[marandaneto]

reason is https://github.com/getsentry/sentry-android-gradle-plugin/pull/212/files latest MAVEN_PUBLISH does not generate the pom file, maybe an issue with AGP 7.x, since 0.15.1 works just fine, we didn't find any breaking change (changelog) that we should act tho.