**Affected version:** 8.2 - 8.5.2
**Fixed in:** 8.5.3

### Problem Description

The problem applies to transforms that use more than 1 CCS cluster or 1 local and 1 CCS as source. A typical source could look like this (the important part: `remotes*`):

```
        "index" : [
          "remotes*:filebeat*"
        ],

```

If 2 indices share the same name the transform might fail with an error similar to this:

```
 Failed to retrieve checkpoint due to: Duplicate key logs-2022-11-14 (attempted merging values [... and ...]
```

Similar to the above the `_stats` call is broken for such a transform, it can fail with an error message starting with:

```
Failure during checkpoint retrieval
```

This can happen even if the transform is in state `STOPPED` or `FAILED`.

### Mitigation

Choose _one_ of the following mitigations:

 - split your transforms to use max 1 CCS/local indices

_or_

 - avoid upgrading to 8.2, until the issue got resolved (this is a regression of #80984)

_or_

 - avoid duplicate names for your indices even on remote cluster, e.g. name the index: `remote1-filebeat...`, `remote2-filebeat...`


### Solution

This is a regression of #80984 which introduced a new way of check-pointing. The remote needs to be prefixed to the index name.
x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/checkpoint/DefaultCheckpointProvider.java
private static void getCheckpointsFromOneClusterBWC(
        Client client,
        Map<String, String> headers,
        String[] indices,
        String cluster,
        ActionListener<Map<String, long[]>> listener
    ) {
        
        GetIndexRequest getIndexRequest = new GetIndexRequest().indices(indices)
            .features(new GetIndexRequest.Feature[0])
            .indicesOptions(IndicesOptions.LENIENT_EXPAND_OPEN);
        ClientHelper.executeWithHeadersAsync(
            headers,
            ClientHelper.TRANSFORM_ORIGIN,
            client,
            GetIndexAction.INSTANCE,
            getIndexRequest,
            ActionListener.wrap(getIndexResponse -> {
                Set<String> userIndices = getIndexResponse.getIndices() != null
                    ? new HashSet<>(Arrays.asList(getIndexResponse.getIndices()))
                    : Collections.emptySet();
                
                ClientHelper.executeAsyncWithOrigin(
                    client,
                    ClientHelper.TRANSFORM_ORIGIN,
                    IndicesStatsAction.INSTANCE,
                    new IndicesStatsRequest().indices(indices).clear().indicesOptions(IndicesOptions.LENIENT_EXPAND_OPEN),
                    ActionListener.wrap(response -> {
                        if (response.getFailedShards() != 0) {
                            for (int i = 0; i < response.getShardFailures().length; ++i) {