[Integ] Modify the selection of AMI type and OS for testing

[himani2411]

Description of changes

• Modify the selection of AMI type and OS for testing
• USe China specific service for VPC endpoints (Only Ec2 and Imagebuilder has different domains)

cookbook aws/aws-parallelcluster-cookbook#3158

Tests

• test_build_image_no_internet in China + govcloud partition

References

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