populate_db: Use do_create_realm for creating zulip realm.

Since do_create_realm also creates general and core team streams,
we rename general to verona right after the realm is created. Mostly
because we dont really want two additional streams and this might
probably make it easy to review things.

There are puppeteer test changes because, we have a new "core team"
stream in tests as well as there is a new default notification stream
"Verona". Because of this tests in message-basics for example have
to be changed since the newly added core team affects the order in
which we navigate through the streams using arrow keys.

The extra await for selector was added in subscriptions test to make
the tests wait. Without the await the tests were passing ocassionally
and failing in some other times.

Fixes #6967

zerver/openapi/python_examples.py

@@ -512,7 +512,7 @@ def get_streams(client: Client) -> None:
     # {code_example|end}
 
     validate_against_openapi_schema(result, "/streams", "get", "200")
-    assert len(result["streams"]) == 4
+    assert len(result["streams"]) == 5
 
 
 @openapi_test_function("/streams/{stream_id}:patch")