[dotnet] Simplify PopupWindowFinder.Invoke

[RenderMichael]

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Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

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PR Type

Enhancement

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Description

• Simplified the PopupWindowFinder.Invoke method logic.

• Removed redundant GetDifference helper method.

• Improved readability and reduced code complexity.

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Changes walkthrough 📝

	Relevant files
Enhancement	PopupWindowFinder.cs Simplified popup handle detection logic.                                  dotnet/src/support/UI/PopupWindowFinder.cs Replaced custom difference logic with LINQ Except method. Removed the GetDifference helper method. Simplified the Invoke method by directly using LINQ for handle comparison. +3/-26

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⏱️ Estimated effort to review: 1 🔵⚪⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Missing Wait Function The lambda expression for the wait.Until method is incomplete. The code defines a lambda but doesn't specify what function it should perform. The return statement is inside the lambda but not connected to the wait.Until call. string popupHandle = wait.Until(driver => { ReadOnlyCollection<string> newHandles = driver.WindowHandles; return newHandles.Except(existingHandles, StringComparer.Ordinal).FirstOrDefault(); });

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PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Handle potential null return The FirstOrDefault() method can return null when no new handles are found, but the method signature expects a non-nullable string. Add null handling to avoid potential NullReferenceException. dotnet/src/support/UI/PopupWindowFinder.cs [137] -return newHandles.Except(existingHandles, StringComparer.Ordinal).FirstOrDefault(); +var newHandle = newHandles.Except(existingHandles, StringComparer.Ordinal).FirstOrDefault(); +return newHandle ?? string.Empty; Apply this suggestion Suggestion importance[1-10]: 8 __ Why: The suggestion correctly identifies a potential null reference issue. Since FirstOrDefault() can return null when no new handles are found, but the method returns a non-nullable string, adding null handling prevents a potential NullReferenceException in consuming code.	Medium
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