[GEODE-10630] The source distribution does not complete ./gradlew build

[JinwooHwang]

Cause

The src distribution in geode-assembly/build.gradle picks up .buildinfo twice:

1. from rootProject.tasks.writeBuildInfo, which places the generated file at the archive root.
2. from (rootDir), which sweeps the whole tree.

In a git checkout there is no $rootDir/.buildinfo, so only the first source contributes and the build passes. An unpacked source distribution already carries .buildinfo at its root, so the second source picks it up as well and Gradle 7 fails on the duplicate entry. The existing build/out directory exclusion covers build/.buildinfo but not the root copy.

Fix

Exclude .buildinfo from the rootDir sweep, leaving the writeBuildInfo output as the single authoritative entry. Contents are unchanged, so the source distribution stays reproducible: rebuilding from an unpacked tarball emits the same .buildinfo it shipped with.

Testing

With a .buildinfo placed at the repo root to reproduce the source-distribution layout:

• Before: srcDistTar fails with the duplicate-entry error above.
• After: BUILD SUCCESSFUL, and the archive contains exactly one .buildinfo, holding the real SCM values rather than the root copy.

For all changes, please confirm:

• Is there a JIRA ticket associated with this PR? Is it referenced in the commit message?
• Has your PR been rebased against the latest commit within the target branch (typically develop)?
• Is your initial contribution a single, squashed commit?
• Does gradlew build run cleanly?
• Have you written or updated unit tests to verify your changes?
• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?