Fix windows py spurious stderr failure (#1885)

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## Summary

On Windows `10.0.19045` the `py` command prints to `stderr` even when
working correctly. This means that uv should not treat this as a
failure.

Fixes #1904

## Test Plan

I ran the modified code and it worked. I expect the pull request to run
automated tests.

crates/uv-interpreter/src/python_query.rs

@@ -364,8 +364,8 @@ mod windows {
             .in_scope(|| Command::new("py").arg("--list-paths").output())
             .map_err(Error::PyList)?;
 
-        // There shouldn't be any output on stderr.
-        if !output.status.success() || !output.stderr.is_empty() {
+        // `py` sometimes prints "Installed Pythons found by py Launcher for Windows" to stderr which we ignore.
+        if !output.status.success() {
             return Err(Error::PythonSubcommandOutput {
                 message: format!(
                     "Running `py --list-paths` failed with status {}",