Config schema generator: Backport latest changes from Aspire

[bart-vmware]

Description

This PR backports the latest changes from the Aspire Configuration Schema Generator.
Based on microsoft/aspire#6312. Targets System.Text.Json v9, which contains breaking changes.

Quality checklist

• Your code complies with our Coding Style.
• You've updated unit and/or integration tests for your change, where applicable.
• You've updated documentation for your change, where applicable.
  If your change affects other repositories, such as Documentation, Samples and/or MainSite, add linked PRs here.
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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[TimHess]

LGTM