Enabling Package validation and moving to GA SDK

[joperezr]

Description

Seems like PackageValidation against a baseline version wasn't really working due to property import order (luckily we didn't introduce breaking changes). This PR enables it back and makes sure that the build fails if we make a change that breaks compatibility against our 9.0.0 package. This change also disables this baseline validation for packages that haven't shipped stable yet. Finally, I'm also moving us to use the GA SDK as part of this change.

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Is this introducing a breaking change?
      • Yes
        • Link to aspire-docs issue (please use this breaking-change template):
      • No
        • Link to aspire-docs issue (please use this doc-idea template):
  • No

Microsoft Reviewers: Open in CodeFlow

[mitchdenny]

Looking forward to getting onto GA bits.

[eerhardt]

LGTM. Thanks @joperezr!