Fix: Date field format parsing for legacy query engine

Description

This is a MR, which aim to fix the issue described over https://github.com/opensearch-project/sql/issues/1545 to align the representation of date field between the legacy engine and the v2 engine.

Code changes highlight:

Remove the break identifier from DateFieldFormatter, the current behaviour will only parse the first date field from the resultSet, which is not a valid assumption, because OpenSearch as platform allow multiple date fields co-exist on an index, also this is not an uncommon use-case for enterprise. Hence all date fields present on any given index should be formatted regardless of the order.
To detect and attempt parse any unix timestamp (second || milisecond) on best-effort basis, OpenSearch as platform allow unix timestamp value to be inserted despite epoch_millis being explicitly specified on field format, in this particular case there is no clear hint from the query indicate this is numeric timestamp from OpenSearch.

Although issue is being reported https://github.com/opensearch-project/sql/issues/1545 under nested-query, however this bug has wider impact outside of nested-query, and the conditions to trigger are:

Query that unsupported by the v2 engine and being forwarded to legacy engine
Multiple date fields are being specified on the Index schema WITHOUT any explicit format configuration.

When this happen, the current behaviour will only parse the first date field from the resultset.

Reference doc:

OpenSearch Product doc mentioning that integer value will also be accepted. https://opensearch.org/docs/latest/field-types/supported-field-types/date/

Testing plan

# Create table
PUT http://localhost:9200/datetype_test?pretty

{
  "mappings": {
    "properties": {
      "dateAsDate": {"type": "date"},
      "longAsDate": {"type": "date"},      
      "id": { "type": "long" },
      "projects": {
        "type": "nested", 
        "properties": {
          "name": { "type": "text", "fields": {"keyword": {"type": "keyword"   }
            }
          }}}}}}

# Insert data
POST http://localhost:9200/datetype_test/_bulk?refresh

{"index":{"_id":"1"}}
{"id":3,"dateAsDate":"2023-01-01T00:00:00", "longAsDate": 1672531200000, "projects":[{"name":"SQL Spectrum querying"},{"name":"SQL security"},{"name":"OpenSearch security"}]}
{"index":{"_id":"2"}}
{"id":4,"dateAsDate":"2024-01-01T00:00:00", "longAsDate": 1704067200000, "projects":[]}
{"index":{"_id":"3"}}
{"id":6,"dateAsDate":"2025-01-01T00:00:00","longAsDate": 1735689600000, "projects":[{"name":"SQL security"},{"name":"Hello security"}]}

#Qeury, both fields should be in simple date format.
POST http://localhost:9200/_plugins/_sql

{
  "query" : "SELECT t.id, t.dateAsDate, t.longAsDate FROM datetype_test AS t, t.projects AS p"
}

Check List

[ ] New functionality includes testing.
[ ] New functionality has been documented.
- [ ] New functionality has javadoc added.
- [ ] New functionality has a user manual doc added.
[ ] API changes companion pull request created.
[x] Commits are signed per the DCO using --signoff.
[ ] Public documentation issue/PR created.

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opensearch-project / sql