Fix msquic performance tests

[Alan-Jowett]

This pull request updates the .github/scripts/run-quic-echo-test.ps1 script and the network-traffic-performance.yml workflow to add support for a new msquicpriv.sys kernel driver, ensure it is properly installed and loaded both locally and remotely, and to update the workflow to track which environments support the msquic-km backend. The changes also update the referenced commit for the WinQuicEcho tool.

Kernel driver management improvements:

• Added Get-MsQuicPrivDriverPath and Ensure-MsQuicPrivLoaded functions to locate and load the new msquicpriv.sys kernel driver. The script now ensures both msquic.sys and msquicpriv.sys are installed and running before loading the WinQuicEcho kernel-mode driver, both locally and remotely. [1] [2] [3]
• Updated the driver installation functions (Install-LocalWinQuicEchoKmDriver, Install-RemoteWinQuicEchoKmDriver, Prepare-WinQuicEchoKmDriver) to require and handle the additional msquicpriv.sys driver. These functions now pass and validate the new driver path, copy it to the target, and set up service dependencies accordingly. [1] [2] [3] [4] [5] [6] [7]

Service dependency changes:

• Changed the WinQuicEcho kernel service dependency from msquic to msquicpriv, ensuring the service only starts after msquicpriv is loaded. This affects both service creation and configuration, locally and remotely. [1] [2] [3] [4]

Workflow and environment updates:

• Updated the network-traffic-performance.yml workflow to reference a new commit of the WinQuicEcho tool and to include a supports_msquic_km flag in the test matrix, indicating which environments support the kernel-mode backend. [1] [2]

These changes ensure that the new msquicpriv.sys driver is always present and active when running kernel-mode echo tests, improving reliability and compatibility for environments that support this backend.