AK/LibCore/LibFileSystem: Use AK/Windows.h instead of windows.h [NFC]

[R-Goc]

This pr changes the remaining includes of windows.h to AK/Windows.h for consistency. In these files probably there wouldn't be future issues with redefinitions that AK/Windows.h avoids, but it doesn't hurt to make it more consistent. Also removes an unnecessary include. (processthreadsapi.h is already included in windows.h)

[ladybird-bot]

Hello!

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[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

[R-Goc]

Unstale

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

[R-Goc]

Unstale

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

[github-actions[bot]]

This pull request has been closed because it has not had recent activity. Feel free to open a new pull request if you wish to still contribute these changes. Thank you for your contributions!