[BUG] Column Info not populating in Add KPI form immediately after adding 3rd party Datasource

[rjdp]

Describe the bug

When adding a KPI immediately after 3rd Party Datasource (verified on Google sheet / Google Analytics), the column details don't populate in metrics/date/dimensions dropdown

Although after few minutes this starts working as expected.

Explain the environment

• Chaos Genius version: release Candidate 0.6.0
• OS Version / Instance: Ubuntu 18.04, AWS EC2
• Deployment type: Docker

Current behavior

Columns dont populate immediately after adding 3rd party datasource, in the Add KPI form when the newly added 3rd party datasource is chosen. Niether User is show any information like to wait for sometime for columns to be available

Expected behavior

Either columns should be available or user should be informed to wait

Screenshots

• for google sheets
  

• for google analytics
  

Additional context

This is an Airbyte specific issue

Logs

For Google Analytics

``` {"asctime": "2022-04-07 07:38:00,106", "levelname": "ERROR", "name": "chaos_genius.views.data_source_view", "message": "Error in data source table info: ga_ec9c_traffic_sources", "lineno": 746, "funcName": "get_table_info", "filename": "data_source_view.py", "exc_info": "Traceback (most recent call last):\n File \"/usr/src/app/chaos_genius/views/data_source_view.py\", line 735, in get_table_info\n table_info = get_table_metadata(ds_data.as_dict, schema, table_name)\n File \"/usr/src/app/chaos_genius/connectors/__init__.py\", line 80, in get_table_info\n table_info[\"columns\"] = db_connection.get_columns(table_name, schema)\n File \"/usr/src/app/chaos_genius/connectors/base_db.py\", line 114, in get_columns\n db_columns = self.inspector.get_columns(table_name=use_table, schema=use_schema)\n File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/engine/reflection.py\", line 497, in get_columns\n col_defs = self.dialect.get_columns(\n File \"\", line 2, in get_columns\n File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/engine/reflection.py\", line 55, in cache\n ret = fn(self, con, *args, **kw)\n File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/dialects/postgresql/base.py\", line 3585, in get_columns\n table_oid = self.get_table_oid(\n File \"\", line 2, in get_table_oid\n File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/engine/reflection.py\", line 55, in cache\n ret = fn(self, con, *args, **kw)\n File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/dialects/postgresql/base.py\", line 3465, in get_table_oid\n raise exc.NoSuchTableError(table_name)\nsqlalchemy.exc.NoSuchTableError: ga_ec9c_traffic_sources"} ```

For Google sheets

{"asctime": "2022-04-07 07:13:09,932", "levelname": "ERROR", "name": "chaos_genius.views.data_source_view", "message": "Error in data source table info: gs_b456_bank_marketing", "lineno": 746, "funcName": "get_table_info", "filename": "data_source_view.py", "exc_info": "Traceback (most recent call last):\n  File \"/usr/src/app/chaos_genius/views/data_source_view.py\", line 735, in get_table_info\n    table_info = get_table_metadata(ds_data.as_dict, schema, table_name)\n  File \"/usr/src/app/chaos_genius/connectors/__init__.py\", line 80, in get_table_info\n    table_info[\"columns\"] = db_connection.get_columns(table_name, schema)\n  File \"/usr/src/app/chaos_genius/connectors/base_db.py\", line 114, in get_columns\n    db_columns = self.inspector.get_columns(table_name=use_table, schema=use_schema)\n  File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/engine/reflection.py\", line 497, in get_columns\n    col_defs = self.dialect.get_columns(\n  File \"<string>\", line 2, in get_columns\n  File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/engine/reflection.py\", line 55, in cache\n    ret = fn(self, con, *args, **kw)\n  File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/dialects/postgresql/base.py\", line 3585, in get_columns\n    table_oid = self.get_table_oid(\n  File \"<string>\", line 2, in get_table_oid\n  File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/engine/reflection.py\", line 55, in cache\n    ret = fn(self, con, *args, **kw)\n  File \"/usr/local/lib/python3.8/dist-packages/sqlalchemy/dialects/postgresql/base.py\", line 3465, in get_table_oid\n    raise exc.NoSuchTableError(table_name)\nsqlalchemy.exc.NoSuchTableError: gs_b456_bank_marketing"}