Ads module e2e tests

[zutigrm]

Summary

Addresses issue:

• Create Ads Module E2E Tests to Cover Basic Module Setup Flow #8314

Relevant technical choices

Note some behaviour changed since this AC was originally written, mostly around how input field shows validation, so E2E implemented here tests the current behaviour of input field validation.

Test case for showing the incomplete module on empty value saved is included in one test case, it didn't seem necessary to duplicate it

PR Author Checklist

• My code is tested and passes existing unit tests.
• My code has an appropriate set of unit tests which all pass.
• My code is backward-compatible with WordPress 5.2 and PHP 5.6.
• My code follows the WordPress coding standards.
• My code has proper inline documentation.
• I have added a QA Brief on the issue linked above.
• I have signed the Contributor License Agreement (see https://cla.developers.google.com/).

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Code Reviewer Checklist

• Run the code.
• Ensure the acceptance criteria are satisfied.
• Reassess the implementation with the IB.
• Ensure no unrelated changes are included.
• Ensure CI checks pass.
• Check Storybook where applicable.
• Ensure there is a QA Brief.

Merge Reviewer Checklist

• Ensure the PR has the correct target branch.
• Double-check that the PR is okay to be merged.
• Ensure the corresponding issue has a ZenHub release assigned.
• Add a changelog message to the issue.

[tofumatt]

Looks good, just some spec test naming tweaks and such but I'll commit them then get this merged 👍🏻