Fix flakey test by disabling EC2 metadata lookup in test case

[kevinawoo]

Summary

• Disable EC2 IMDS lookups inside TestCreateWorkerDeploymentVersion_Errors.
• Keep the fake AWS Lambda validation failure deterministic and local.

Root Cause

The test intentionally passes fake AWS Lambda and assume-role inputs. Server-side worker-deployment validation uses go.temporal.io/auto-scaled-workers, which imports the AWS SDK and validates the aws-lambda compute provider. That path builds default AWS config and calls STS/Lambda validation.

Before STS can assume the fake role, the AWS SDK needs base credentials. In a local or CI environment with no AWS env creds/profile/container creds, the AWS SDK falls back to EC2 Instance Metadata Service. Outside EC2, that means waiting on IMDS/network retries even though the test only wants an expected validation failure.

Scope of the Fix

This is broader AWS SDK behavior: AWS_EC2_METADATA_DISABLED=true is useful for any test/process that invokes AWS SDK default credential resolution without real credentials and should not hit EC2 IMDS.

In this CLI test suite, the enabled surface is narrow:

• TestCreateWorkerDeploymentVersion_Errors is the only enabled test that passes a complete fake AWS Lambda compute config to the server.
• The later missing-field subcases in that same test fail in CLI-side validation before server-side AWS validation.
• TestCreateWorkerDeploymentVersion_LambdaComputeConfig would also hit the AWS path, but it is skipped because it needs real AWS fixtures.

So the fix is intentionally test-local rather than package-wide, to avoid changing behavior for future tests that might intentionally exercise AWS credential resolution.

Validation

• go test -mod=readonly ./internal/temporalcli -run 'TestSharedServerSuite/TestCreateWorkerDeploymentVersion_Errors' -count=1 -v