[TESTING] Added extension methods to support deploying app service environment to a slot

[ShilpiRach]

Description

• Added 2 extension methods to accept DeploymentSlot as a string or resource parameter
• If DeploymentSlot is specified, all built project images are deployed to the slot and not the main web app (this includes dashboard)
  • Ensure that the endpoint references are resolved to the respective slots and not the main web app (i.e. staging slot of a web app will refer to the staging slot of another web app).

Fixes #9667

Tested manually by deploying to slots https://ms.portal.azure.com/#@microsoft.onmicrosoft.com/resource/subscriptions/bef29afb-3c08-4894-ae64-43bdd8f3f447/resourceGroups/rg-aspireapp32-slot/overview

UTs pending

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
    • Link to aspire-docs issue (consider using one of the following templates):
      • New (or update) doc-idea template
      • New breaking-change template
      • New diagnostic template
  • [ ] No

[github-actions[bot]]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 12810

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 12810"