Adopt MSVC 14.50 and fix C4874 assignment-as-condition in Grapher.cpp

[michaelbprice]

Fixes #2360.

cppbuildtoolsupgrade_01921b.zip

Description of the changes:

• Updates .vcxproj files to use PlatformToolset v145 instead of v143
• Refactored line 376 to extract assignment before condition check

How changes were validated:

I was unable to successfully run the CalculatorUITests locally. After getting WinAppDriver installed and Developer Mode settings adjusted, it gave me an error

Class Initialization method CalculatorUITests.CurrencyConverterFunctionalTests.ClassInitialize threw exception. OpenQA.Selenium.WebDriverException: OpenQA.Selenium.WebDriverException: Package was not found. (Exception from HRESULT: 0x80073CF1).

I received a similar error when trying to run the CalculatorUnitTests project, but these were dialog popups, not exceptions listed in Test Explorer.

The changes are trivial, but should be tested by someone with that capability before merging.

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These changes were made by GitHub Copilot app modernization for C++, which is now in public preview. I am attaching a .zip file with the generated Markdown files laying out the analysis, plan, tasks, and execution summary, in case you want to examine Copilot's "reasoning" on the issues discovered.

It also diagnosed the deprecated /await switch as mentioned in #2404, but I instructed Copilot to not resolve those warnings as a part of this effort.

[michaelbprice]

I did a force push to correct a mistake I made with my commits. The original commit included the Copilot markdown files. I had amended that commit to remove them, but then didn't reset my working branch correctly to that commit. It is now corrected.

[michaelbprice]

It looks like the build fails because the runner being used doesn't have Visual Studio 2026 and MSVC 14.50 installed on it. Feel free to keep this PR around until that's resolved, or cancel and I can resubmit it at a later time. OR we could just pull out the warning fix, as it is valid for v143 as well.