Google Ads Source: Annotate oauth flow init parameters

[sherifnada]

What

Describe what the change is solving
It helps to add screenshots if it affects the frontend.

How

Describe the solution

Recommended reading order

1. spec.json
2. the rest

Pre-merge Checklist

Community member or Airbyter

• Grant edit access to maintainers (instructions)
• Secrets in the connector's spec are annotated with airbyte_secret
• Unit & integration tests added and passing. Community members, please provide proof of success locally e.g: screenshot or copy-paste unit, integration, and acceptance test output. To run acceptance tests for a Python connector, follow instructions in the README. For java connectors run ./gradlew :airbyte-integrations:connectors:<name>:integrationTest.
• Code reviews completed
• Documentation updated
  • Connector's README.md
  • Connector's bootstrap.md. See description and examples
  • Changelog updated in docs/integrations/<source or destination>/<name>.md including changelog. See changelog example
• PR name follows PR naming conventions
• Connector version bumped like described here

Airbyter

If this is a community PR, the Airbyte engineer reviewing this PR is responsible for the below items.

• Create a non-forked branch based on this PR and test the below items on it
• Build is successful
• Credentials added to Github CI. Instructions.
• /test connector=connectors/<name> command is passing.
• New Connector version released on Dockerhub by running the /publish command described here

[sherifnada]

/publish connector=connectors/source-google-ads

🕑 connectors/source-google-ads https://github.com/airbytehq/airbyte/actions/runs/1230615650
✅ connectors/source-google-ads https://github.com/airbytehq/airbyte/actions/runs/1230615650