Add calls to get snapshot info

Author: samxbr

x-pack/plugin/slm/src/main/java/org/elasticsearch/xpack/slm/SnapshotLifecycleService.java

@@ -239,9 +239,7 @@ public static String getJobId(SnapshotLifecyclePolicyMetadata policyMeta) {
      */
     public static String getPolicyId(String jobId) {
         int lastDashIndex = jobId.lastIndexOf('-');
-        if (lastDashIndex == -1) {
-            throw new IllegalArgumentException("Invalid job id format: " + jobId);
-        }
+        assert lastDashIndex != -1 : "Invalid job id format: " + jobId;
         return jobId.substring(0, lastDashIndex);
     }