MM-31391: Add max connection idle timeout to config (#16792)

* Update config.go

* Update telemetry.go

* Update store and store test

* Update settings.go

* use new error code

* Trigger CI

Co-authored-by: Haardik Dharma <dharmahaardik08@gmail.com>

model/config.go

@@ -1091,6 +1091,7 @@ type SqlSettings struct {
 	DataSourceSearchReplicas    []string `access:"environment,write_restrictable,cloud_restrictable"`
 	MaxIdleConns                *int     `access:"environment,write_restrictable,cloud_restrictable"`
 	ConnMaxLifetimeMilliseconds *int     `access:"environment,write_restrictable,cloud_restrictable"`
+	ConnMaxIdleTimeMilliseconds *int     `access:"environment,write_restrictable,cloud_restrictable"`
 	MaxOpenConns                *int     `access:"environment,write_restrictable,cloud_restrictable"`
 	Trace                       *bool    `access:"environment,write_restrictable,cloud_restrictable"`
 	AtRestEncryptKey            *string  `access:"environment,write_restrictable,cloud_restrictable"`
@@ -1137,6 +1138,10 @@ func (s *SqlSettings) SetDefaults(isUpdate bool) {
 		s.ConnMaxLifetimeMilliseconds = NewInt(3600000)
 	}
 
+	if s.ConnMaxIdleTimeMilliseconds == nil {
+		s.ConnMaxIdleTimeMilliseconds = NewInt(300000)
+	}
+
 	if s.Trace == nil {
 		s.Trace = NewBool(false)
 	}
@@ -3241,6 +3246,10 @@ func (s *SqlSettings) isValid() *AppError {
 		return NewAppError("Config.IsValid", "model.config.is_valid.sql_conn_max_lifetime_milliseconds.app_error", nil, "", http.StatusBadRequest)
 	}
 
+	if *s.ConnMaxIdleTimeMilliseconds < 0 {
+		return NewAppError("Config.IsValid", "model.config.is_valid.sql_conn_max_idle_time_milliseconds.app_error", nil, "", http.StatusBadRequest)
+	}
+
 	if *s.QueryTimeout <= 0 {
 		return NewAppError("Config.IsValid", "model.config.is_valid.sql_query_timeout.app_error", nil, "", http.StatusBadRequest)
 	}