Exclude Basic scaling and add explicit automatic scaling to App Engine

[KannetiDivya4a7]

Replaced basic scaling with explicit automatic scaling in App Engine sample to fix diff issue.

Per b/325645138, this rolls back #10000, which was intended to be a temporary fix.

Tested Scenarios:
Removing basic scaling: Commented out the basic scaling configuration causes a test failure/phantom diff because myapp_v2 inherits configuration from myapp_v1.
Switching to explicit automatic scaling: Resolves the diff issues and the tests pass successfully.

appengine: fixed diff in `google_app_engine_standard_app_version` sample

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[github-actions]

Googlers: For automatic test runs see go/terraform-auto-test-runs.

@melinath, a repository maintainer, has been assigned to review your changes. If you have not received review feedback within 2 business days, please leave a comment on this PR asking them to take a look.

You can help make sure that review is quick by doing a self-review and by running impacted tests locally.

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes for commit 9ee8f0b:

Diff report

Your PR generated the following diffs in downstream repositories:

Repository	Diff Link	Changes
google provider	View Diff	2 files changed, 24 insertions(+), 4 deletions(-)
google-beta provider	View Diff	2 files changed, 24 insertions(+), 4 deletions(-)

Test report

Analytics

Total Tests	Passed	Skipped	Affected
16	12	3	1

Affected Service Packages

• appengine

Learn how VCR tests work

---

Step 1: Replaying Mode

Action taken

Found 1 affected test(s) by replaying old test recordings. Starting RECORDING based on the most recent commit.

Click here to see the affected tests

• TestAccAppEngineStandardAppVersion_appEngineStandardAppVersionExample

View the replaying VCR build log

---

Step 2: Recording Mode

Recording Mode	Replaying Rerun	Test Name
✅ Log	✅	TestAccAppEngineStandardAppVersion_appEngineStandardAppVersionExample

🟢 All tests passed!

View the recording VCR build log or the debug logs folder for detailed results.

@KannetiDivya4a7, @melinath VCR tests complete for 9ee8f0b!

[melinath]

I don't think this test has any diffs that need to be fixed.