Warn on requirements.txt-provided arguments in uv run et al (#5364)

## Summary

Also applies to `uv tool run` and `uv tool install`.

Closes https://github.com/astral-sh/uv/issues/5349.

crates/distribution-types/src/index_url.rs

@@ -386,6 +386,11 @@ impl<'a> IndexLocations {
         self.flat_index.iter()
     }
 
+    /// Return the `--no-index` flag.
+    pub fn no_index(&self) -> bool {
+        self.no_index
+    }
+
     /// Clone the index locations into a [`IndexUrls`] instance.
     pub fn index_urls(&'a self) -> IndexUrls {
         IndexUrls {