Promote Python APIs to Stable in Aspire Templates

[davidfowl]

Summary

Update Aspire templates to use stable Python APIs instead of experimental ones. Ensure all references and documentation reflect this change.

Motivation

Providing stable APIs improves reliability, developer confidence, and adoption among Python users. This makes Aspire templates more production-ready and avoids confusion regarding experimental features.

Tasks

• Identify all experimental Python API usages
• Replace with stable API versions
• Update documentation and code samples
• Validate template behavior with non-experimental APIs

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Relates to parent issue: Aspire Python Templates for Python Backend and Javascript Frontend