Esql - support date nanos in date format function (#120143)

This adds support for passing Date Nanos into the Date Format function. It works for both the single argument and two argument versions. Format strings are unchanged, as the same formatting logic works for both resolutions.

resolves #109994

---------

Co-authored-by: elasticsearchmachine <[email protected]>

Author: not-napoleon

docs/changelog/120143.yaml

@@ -0,0 +1,6 @@
+pr: 120143
+summary: Esql - support date nanos in date format function
+area: ES|QL
+type: enhancement
+issues:
+ - 109994

docs/reference/esql/functions/kibana/definition/date_format.json

@@ -1226,3 +1226,25 @@ FROM date_nanos
 millis:date              | nanos:date_nanos               | num:long
 2023-10-23T12:27:28.948Z | 2023-10-23T12:27:28.948000000Z | 1698064048948000000
 ;
+
+Date Nanos Format
+required_capability: date_nanos_date_format
+
+FROM date_nanos
+| EVAL sv_nanos = MV_MAX(nanos)
+| EVAL a = DATE_FORMAT(sv_nanos), b = DATE_FORMAT("yyyy-MM-dd", sv_nanos), c = DATE_FORMAT("strict_date_optional_time_nanos", sv_nanos)
+| KEEP sv_nanos, a, b, c;
+ignoreOrder:true
+
+sv_nanos:date_nanos               | a:keyword             | b:keyword  | c:keyword
+2023-10-23T13:55:01.543123456Z | 2023-10-23T13:55:01.543Z | 2023-10-23 | 2023-10-23T13:55:01.543123456Z
+2023-10-23T13:53:55.832987654Z | 2023-10-23T13:53:55.832Z | 2023-10-23 | 2023-10-23T13:53:55.832987654Z
+2023-10-23T13:52:55.015787878Z | 2023-10-23T13:52:55.015Z | 2023-10-23 | 2023-10-23T13:52:55.015787878Z
+2023-10-23T13:51:54.732102837Z | 2023-10-23T13:51:54.732Z | 2023-10-23 | 2023-10-23T13:51:54.732102837Z
+2023-10-23T13:33:34.937193000Z | 2023-10-23T13:33:34.937Z | 2023-10-23 | 2023-10-23T13:33:34.937193Z
+2023-10-23T12:27:28.948000000Z | 2023-10-23T12:27:28.948Z | 2023-10-23 | 2023-10-23T12:27:28.948Z
+2023-10-23T12:15:03.360103847Z | 2023-10-23T12:15:03.360Z | 2023-10-23 | 2023-10-23T12:15:03.360103847Z
+2023-10-23T12:15:03.360103847Z | 2023-10-23T12:15:03.360Z | 2023-10-23 | 2023-10-23T12:15:03.360103847Z
+2023-03-23T12:15:03.360103847Z | 2023-03-23T12:15:03.360Z | 2023-03-23 | 2023-03-23T12:15:03.360103847Z
+2023-03-23T12:15:03.360103847Z | 2023-03-23T12:15:03.360Z | 2023-03-23 | 2023-03-23T12:15:03.360103847Z
+;