Exposing TimeEstimate field in the API (#35475)

Time Estimate field is not included in the issue modification webhooks
or issue API endpoints.

This PR fixes the field for the API.

---------

Signed-off-by: Gnanakeethan Balasubramaniam <gnanakeethan@users.noreply.github.com>
Signed-off-by: Gnanakeethan Balasubramaniam <gnanakeethan@cloudparallax.com>

templates/swagger/v1_json.tmpl

@@ -25728,6 +25728,11 @@
         "state": {
           "$ref": "#/definitions/StateType"
         },
+        "time_estimate": {
+          "type": "integer",
+          "format": "int64",
+          "x-go-name": "TimeEstimate"
+        },
         "title": {
           "type": "string",
           "x-go-name": "Title"