**Apache Airflow version**: 2.0.0

**Kubernetes version (if you are using kubernetes)** (use `kubectl version`): n/a

**Environment**: Linux

- **Cloud provider or hardware configuration**: amd64
- **OS** (e.g. from /etc/os-release): Centos 7
- **Kernel** (e.g. `uname -a`):
- **Install tools**: pip
- **Others**:

**What happened**:

The field `sql` is rendered as a serialized json `["select 1 from dual", "select 2 from dual"]` instead of a list of syntax-highlighted SQL statements.

![image](https://user-images.githubusercontent.com/5377410/106365382-2f8a1e80-6370-11eb-981a-43bf71e7b396.png)

**What you expected to happen**:

`lists` and `dicts` should be rendered as lists and dicts rather than serialized json unless the `template_field_renderer` is `json`

![image](https://user-images.githubusercontent.com/5377410/106365216-f3a28980-636e-11eb-9c48-15deb1fbe0d7.png)


**How to reproduce it**:

```
from airflow import DAG
from airflow.providers.oracle.operators.oracle import OracleOperator

with DAG("demo", default_args={owner='airflow'}, start_date= pendulum.yesterday(), schedule_interval='@daily',) as dag:
    OracleOperator(task_id='single', sql='select 1 from dual')
    OracleOperator(task_id='list', sql=['select 1 from dual', 'select 2 from dual'])
```

**Anything else we need to know**:

Introduced by #11061, .

A quick and dirty work-around:

Edit file [airflow/www/views.py](https://github.com/PolideaInternal/airflow/blob/13ba1ec5494848d4a54b3291bd8db5841bfad72e/airflow/www/views.py#L673)

```
            if renderer in renderers:
-                if isinstance(content, (dict, list)):
+               if isinstance(content, (dict, list)) and renderer is renderers['json']:
                    content = json.dumps(content, sort_keys=True, indent=4)
                html_dict[template_field] = renderers[renderer](content)
```
airflow/www/views.py
"""Export variables."""
        var_dict = {}
        decoder = json.JSONDecoder()
        for var in items:
            try:
                val = decoder.decode(var.val)
            except Exception:  
                val = var.val
            var_dict[var.key] = val
        response = make_response(json.dumps(var_dict, sort_keys=True, indent=4))
        response.headers["Content-Disposition"] = "attachment; filename=variables.json"
        response.headers["Content-Type"] = "application/json; charset=utf-8"
        return response
    @expose('/varimport', methods=["POST"])
    @action_logging
    def varimport(self):
        """Import variables"""
        try:
            out = request.files['file'].read()
            if isinstance(out, bytes):
                variable_dict = json.loads(out.decode('utf-8'))
            else:
                variable_dict = json.loads(out)
        except Exception:  
            self.update_redirect()
            flash("Missing file or syntax error.", 'error')
            return redirect(self.get_redirect())