Backport of #25763 to release/v7.6

Triggered by @adityapatwardhan on behalf of @kilasuit

Original CL Label: CL-Engine

/cc @PowerShell/powershell-maintainers

Impact

REQUIRED: Choose either Tooling Impact or Customer Impact (or both). At least one checkbox must be selected.

Tooling Impact

• Required tooling change
• Optional tooling change (include reasoning)

Customer Impact

• Customer reported
• Found internally

This fixes a long-standing quirk in how aliased commands display their resolved command names. The change improves user experience by consistently showing alias -> resolved command mapping for better discoverability. This is an engine improvement that affects how Get-Alias displays command information.

Regression

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• Yes
• No

This is not a regression.

Testing

Original PR added comprehensive tests in Get-Alias.Tests.ps1 to verify that DisplayName always shows the correct "AliasName -> ResolvedCommand" format for all aliases. The fix was verified to resolve issue #25616.

Risk

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• High
• Medium
• Low

This is a display/formatting improvement in the engine's alias system with comprehensive test coverage. The change is isolated to the DisplayName script property logic and doesn't affect core command execution or critical functionality.