Fix duplicate CVE numbers showing up multiple times in because text /…

… commit messages

src/main/java/org/openrewrite/java/dependencies/DependencyVulnerabilityCheck.java

@@ -323,6 +323,7 @@ private static String because(Collection<MinimumDepthVulnerability> reasons) {
                 .map(MinimumDepthVulnerability::getVulnerability)
                 .map(Vulnerability::getCve)
                 .filter(StringUtils::isNotEmpty)
+                .distinct()
                 .collect(Collectors.joining(", "));
         return StringUtils.isBlank(because) ? null : because;
     }