Today we log a "deleting snapshots [...] from repository [...]" message at INFO level [almost the first thing](https://github.com/elastic/elasticsearch/blob/dfaec0dbf0c8a0ba2912381334019725848f1f5a/server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java#L1886-L1888) when we start the deletion. However, the requested snapshots may not exist or they may be wildcards to be matched against actual snapshots. In these cases, the log message is either misleading or insuffiicent. Instead we should log the message after we have successfully added the delete to the cluster state similar to how the [logging works for snapshot creation](https://github.com/elastic/elasticsearch/blob/f77c16b78bab5e9f3ee24974aeba408e254e8c94/server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java#L3804).
server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java
}
            assert assertConsistent();
            return res;
        }
        boolean startDeletion(String deleteUUID) {
            return runningDeletions.add(deleteUUID);
        }
        void finishDeletion(String deleteUUID) {
            runningDeletions.remove(deleteUUID);
        }
        synchronized void addFinalization(Snapshot snapshot, Metadata metadata) {
            snapshotsToFinalize.computeIfAbsent(snapshot.getRepository(), k -> new LinkedList<>()).add(snapshot);
            this.latestKnownMetaData = metadata;
            assertConsistent();
        }
        /**
         * Clear all state associated with running snapshots. To be used on master-failover if the current node stops
         * being master.
         */
        synchronized void clear() {
            snapshotsToFinalize.clear();
            runningDeletions.clear();
            latestKnownMetaData = null;
        }
        synchronized boolean isEmpty() {
            return snapshotsToFinalize.isEmpty();
        }
        synchronized boolean assertNotQueued(Snapshot snapshot) {
            assert snapshotsToFinalize.getOrDefault(snapshot.getRepository(), new LinkedList<>())
                .stream()