feat(alert/report): chart as csv format attachment for email and slack (#13828)

* add ui for setting report format

* refactor default notification format

* init csv data alert report

* add report format to report_schedule model

* add ALERTS_ATTACH_REPORTS feature flag

* fix lint

* update check image tag

* fix migrations

Co-authored-by: samtfm <sam@preset.io>

superset/utils/csv.py

@@ -15,7 +15,9 @@
 # specific language governing permissions and limitations
 # under the License.
 import re
-from typing import Any
+import urllib.request
+from typing import Any, Dict, Optional
+from urllib.error import URLError
 
 import pandas as pd
 
@@ -65,3 +67,20 @@ def df_to_escaped_csv(df: pd.DataFrame, **kwargs: Any) -> Any:
     df = df.applymap(escape_values)
 
     return df.to_csv(**kwargs)
+
+
+def get_chart_csv_data(
+    chart_url: str, auth_cookies: Optional[Dict[str, str]] = None
+) -> Optional[bytes]:
+    content = None
+    if auth_cookies:
+        opener = urllib.request.build_opener()
+        cookie_str = ";".join([f"{key}={val}" for key, val in auth_cookies.items()])
+        opener.addheaders.append(("Cookie", cookie_str))
+        response = opener.open(chart_url)
+        content = response.read()
+    if response.getcode() != 200:
+        raise URLError(response.getcode())
+    if content:
+        return content
+    return None