fix(installer): kill venv processes before removing venv dir (#47557)

[kyssta-exe]

Fixes #47557. On Windows, scripts/install.ps1 recreates the venv by removing the old directory, but python.exe and pythonw.exe processes holding .pyd native extensions as loaded DLLs prevent deletion. The fix kills hermes.exe, python.exe, and pythonw.exe processes running from the venv before removal, with a retry if the first Remove-Item fails.

[alt-glitch]

Duplicate of #46726 — both PRs fix #47557 with the same mechanism: stop processes running out of the venv (hermes.exe/python.exe/pythonw.exe) before Remove-Item venv on Windows, since they hold .pyd native extensions as loaded DLLs. The earlier-open #46726 matches venv-resident processes by ExecutablePath (image-name-agnostic); this PR restricts to the three image names filtered by proc.Path under venv\Scripts and adds a retry. Same approach, so closing as duplicate of the canonical #46726 (which #47569 also duplicates). The retry-on-failure idea here is a nice touch worth folding into #46726.

[kyssta-exe]

Stale — oldest open PR, no merge activity for weeks.