**Apache Airflow version**:
apache/airflow:1.10.11

**Kubernetes version (if you are using kubernetes)** (use `kubectl version`):
v1.16.11-gke.5

**Environment**:
GKE


**What happened**:
Webserver doesn't fetch logs for tasks from elasticsearch

**What you expected to happen**:
task logs will be displayed in the webserver UI

It seems like the webserver is trying to query task logs by the `log_id` field:
https://github.com/apache/airflow/blob/1.10.11/airflow/utils/log/es_task_handler.py#L175

this field is missing from all log lines (which are written to stdout) using the KubernetesExecutor. Example log line:
`{"asctime": null, "filename": "standard_task_runner.py", "lineno": 77, "levelname": "INFO", "message": "Running: ['airflow', 'run', 'hello_world', 'hello_task_3', '2020-08-19T14:26:07.226064+00:00', '--job_id', '158', '--pool', 'default_pool', '--raw', '-sd', '/opt/airflow/dags/repo/dags/hello_world.py', '--cfg_path', '/tmp/tmpt7lafkaf']", "dag_id": "hello_world", "task_id": "hello_task_3", "execution_date": "2020_08_19T14_26_07_226064", "try_number": "1"}`


**How to reproduce it**:
this is the relevant configuration we have, scheduler and webserver running separately and tasks run using KubernetsExecutor (all in the same cluster/namespace):
```
AIRFLOW__CORE__LOGGING_LEVEL: INFO
AIRFLOW__CORE__REMOTE_LOGGING: "True"
AIRFLOW__ELASTICSEARCH__HOST: http://elasticsearch.logging:9200
AIRFLOW__ELASTICSEARCH__JSON_FORMAT: "True"
AIRFLOW__ELASTICSEARCH__WRITE_STDOUT: "True"
```

we are using fluentd (https://github.com/fluent/fluentd-kubernetes-daemonset) to forward log lines to elasticsearch, all task logs are written to stdout + elasticsearch as expected.
airflow/providers/elasticsearch/log/es_task_handler.py
#
#
#
import logging
import sys
from datetime import datetime
from typing import Optional, Tuple
from urllib.parse import quote
import elasticsearch
import pendulum
from elasticsearch_dsl import Search
from airflow.configuration import conf
from airflow.models import TaskInstance
from airflow.utils import timezone
from airflow.utils.helpers import parse_template_string
from airflow.utils.log.file_task_handler import FileTaskHandler
from airflow.utils.log.json_formatter import JSONFormatter
from airflow.utils.log.logging_mixin import LoggingMixin
class ElasticsearchTaskHandler(FileTaskHandler, LoggingMixin):