[BUG] ListIOCsAPI total hits, and findings count per IOC are incorrect

[AWSHurneyt]

What is the bug?
The "total" count returned by the ListIOCs API currently maxes at 10,000. This count should be the total number of IOCs that match the query.

The "numFindings" count for each IOC also currently maxes at 10,000. The query used to collect this count should ideally be refactored to an aggregation. Only the count of findings for each IOC needs to be returned.

[AWSHurneyt]

The "total" count returned by the ListIOCs API currently maxes at 10,000. This count should be the total number of IOCs that match the query.

Started troubleshooting this locally by ingesting 10k IOCs in addition to the 609 IOCs that are ingested by the prepackaged AlienVault source.

GET localhost:9200/_cat/indices/.opensearch-sap-iocs-*?expand_wildcards=all&v
...
health status index                                                                uuid                   pri rep docs.count docs.deleted store.size pri.store.size
yellow open   .opensearch-sap-iocs-alienvault_reputation_ip_database-1729036845680 NLD2d9EmSN2XJFQVQyd6KA   1   1        609            0    253.7kb        253.7kb
yellow open   .opensearch-sap-iocs-uocgkpibvxtjl5g-zmls-1729036868686              GHLTDu7jSEGTYi7Z9CLMRg   1   1      10000            0      2.4mb          2.4mb

---

As called out above, the ListIOCs API incorrectly returns a maximum total of 10k.

GET localhost:9200/_plugins/_security_analytics/threat_intel/iocs?size=0
...
{
  "total": 10000,
  "iocs": []
}

---

However, even a general search query against the .opensearch-sap-iocs-* index pattern returns a total hit count of 10k.

GET localhost:9200/.opensearch-sap-iocs-*/_search
Content-Type: application/json
{
  "size": 0,
  "query": { "match_all": {} }
}
...
{
  "took": 17,
  "timed_out": false,
  "_shards": {
    "total": 2,
    "successful": 2,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 10000,
      "relation": "gte"
    },
    "max_score": null,
    "hits": []
  }
}

---

A _count API call shows the correct amount though.

GET localhost:9200/.opensearch-sap-iocs-*/_count
...
{
  "count": 10609,
  "_shards": {
    "total": 2,
    "successful": 2,
    "skipped": 0,
    "failed": 0
  }
}

[AWSHurneyt]

Regarding #1191 (comment), _search requests require track_total_hits to be set to true to return a hits.total.value greater than 10k.

I'll refactor this locally to fixed that portion of this bug report.