chore: drop Aspire.Cli.Tests unwanted dependencies

[DeagleGross]

This PR moves the existing "e2e" tests validating aspire exec scenario, and drops the unwanted dependencies such as playground apps of the Aspire.Cli.Tests project.

Fixes #10421

[Copilot]

Pull Request Overview

This PR restructures and cleans up the end-to-end tests for the aspire exec feature by moving them into the Aspire.Hosting.Tests project and removing the old Aspire.Cli.Tests suite along with unwanted project dependencies.

• Introduces a new ProjectResourceExecTests class and ExecTestsBase helper in Aspire.Hosting.Tests for backchannel-based exec testing.
• Deletes the legacy E2E exec tests in tests/Aspire.Cli.Tests/E2E/ExecTests.cs.
• Cleans up Aspire.Cli.Tests.csproj by removing references to Aspire.TestUtilities and playground apps.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
tests/Aspire.Hosting.Tests/Backchannel/Exec/ProjectResourceExecTests.cs	Adds new backchannel-based exec tests for project resources
tests/Aspire.Hosting.Tests/Backchannel/Exec/ExecTestsBase.cs	Adds base class for shared exec test logic
tests/Aspire.Cli.Tests/E2E/ExecTests.cs	Removes old E2E exec tests and their dependencies
tests/Aspire.Cli.Tests/Aspire.Cli.Tests.csproj	Drops unwanted project references (TestUtilities and playground apps)

[mitchdenny]

I think we might need a bit more test coverage on the CLI side which simulates various error conditions coming back across a fake backchannel.

If you look at ExecCommand_ExecutesSuccessfully it creates a fake back channel (good) but we aren't using it to simulate various failure states with the exec resource itself and then testing out the CLI behaves.

These new tests without the external project dependency look OK though so I'll approve this PR.

[DeagleGross]

I think we might need a bit more test coverage on the CLI side which simulates various error conditions coming back across a fake backchannel.

i will do in a follow-up pr, merging this to unblock other activities; thanks Mitch!

[mitchdenny]

/backport to release/9.4

[github-actions]

Started backporting to release/9.4: https://github.com/dotnet/aspire/actions/runs/16386346021

[mitchdenny]

@DeagleGross need to remember to backport these PRs :)

[github-actions]

@mitchdenny backporting to "release/9.4" failed, the patch most likely resulted in conflicts:

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch

Applying: drop dependencies
Using index info to reconstruct a base tree...
M	tests/Aspire.Cli.Tests/E2E/ExecTests.cs
Falling back to patching base and 3-way merge...
CONFLICT (modify/delete): tests/Aspire.Cli.Tests/E2E/ExecTests.cs deleted in drop dependencies and modified in HEAD.  Version HEAD of tests/Aspire.Cli.Tests/E2E/ExecTests.cs left in tree.
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0001 drop dependencies
Error: The process '/usr/bin/git' failed with exit code 128

Please backport manually!