Add end-to-end tests of ODK Web Forms flows that involve integration

- [ ] Selects in images: Launch a form with a select with a couple of choices, each with images, validate that the images are displayed, select an option, submit the form, validate that the selected option is reflected in the submission table.
- [ ] Capture image: Launch a form with an image question, select an image, submit the form, validate that the image was submitted

No files or test entry points are named. Start by locating the existing end-to-end integration test setup and its form-launch and submission helpers; done means both checklist flows pass, including image display or capture and the expected submitted value in the submission table.

Written by the indexing model from the issue text.