fix(cyclonedx): Only set licenses at all if they are not empty

This works around [1] and resolves #8857.

[1]: CycloneDX/cyclonedx-core-java#439

Signed-off-by: Sebastian Schuberth <sebastian@doubleopen.org>

plugins/reporters/cyclonedx/src/main/kotlin/CycloneDxReporter.kt

@@ -336,7 +336,7 @@ class CycloneDxReporter : Reporter {
 
             hashes = listOfNotNull(hash)
 
-            licenses = LicenseChoice().apply { licenses = licenseObjects }
+            if (licenseObjects.isNotEmpty()) licenses = LicenseChoice().apply { licenses = licenseObjects }
 
             // TODO: Find a way to associate copyrights to the license they belong to, see
             //       https://github.com/CycloneDX/cyclonedx-core-java/issues/58