### Elasticsearch Version

7.17, 8.x

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

Darwin

### Problem Description

The migrate to data tiers API can sometimes configure an illegal value for the `_tier_preference` setting for partially mounted indices.
This can happen if two conditions are met: 
1. if the partially mounted index doesn't have a `_tier_preference` configured
2. if the migrate to data tiers API doesn't perform any migration for this index (e.g. say this partially mounted index doesn't use the `data` custom attribute name for any allocation filtering, but either uses some other node attribute name or none at all)

In this case this piece of code kicks in to configure a default tier preference https://github.com/elastic/elasticsearch/blob/main/x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/cluster/metadata/MetadataMigrateToDataTiersRoutingService.java#L534

This is wrong, and we should configure the `MountSearchableSnapshotRequest.Storage.defaultDataTiersPreference` as the tier preference.

Relates to https://github.com/elastic/elasticsearch/issues/84758

### Steps to Reproduce

1. Mount an index - `partial-test`
2. Remove the `_tier_preference` using
```
PUT partial-test/_settings
{
  "index.routing.allocation.include._tier_preference": null
}
```
3. Call the migrate to data tiers routing API 
```
POST /_ilm/migrate_to_data_tiers
```

### Logs (if relevant)

_No response_
x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/cluster/metadata/MetadataMigrateToDataTiersRoutingService.java
*    "mappings": {},
     *    "aliases": {}
     *  }
     *  will be migrated to
     *  {
     *    "order": 0,
     *    "index_patterns": [
     *      "*"
     *    ],
     *    "settings": {},
     *    "mappings": {},
     *    "aliases": {}
     *  }
     *
     * Same pattern applies to composable and component templates.
     *
     * If no @param nodeAttrName is provided "data" will be used.
     * If no @param indexTemplateToDelete is provided, no index templates will be deleted.
     *
     * This returns a new {@link ClusterState} representing the migrated state that is ready to use data tiers for index and
     * ILM routing allocations. It also returns a summary of the affected abstractions encapsulated in {@link MigratedEntities}
     */
    public static Tuple<ClusterState, MigratedEntities> migrateToDataTiersRouting(
        ClusterState currentState,
        @Nullable String nodeAttrName,
        @Nullable String indexTemplateToDelete,
        NamedXContentRegistry xContentRegistry,
        Client client,
        XPackLicenseState licenseState,
        boolean dryRun