Rename PythonRequest::Any -> PythonRequest::Default (#7514)

As we support more complex Python discovery behaviors such as:

- #7431 
- #7335 
- #7300 

`Any` is no longer accurate, we actually are looking for a reasonable
default Python version to use which may exclude the first one we find.
Separately, we need the idea of `Any` to improve behavior when listing
versions (e.g., #7286) where we do actually want to match _any_ Python
version. As a first step, we'll rename `Any` to `Default`. Then, we'll
introduce a new `Any` that actually behaves as we'd expect.

crates/uv-python/src/managed.rs

@@ -305,7 +305,7 @@ impl ManagedPythonInstallation {
     pub fn satisfies(&self, request: &PythonRequest) -> bool {
         match request {
             PythonRequest::File(path) => self.executable() == *path,
-            PythonRequest::Any => true,
+            PythonRequest::Default => true,
             PythonRequest::Directory(path) => self.path() == *path,
             PythonRequest::ExecutableName(name) => self
                 .executable()