Take owned Read and Write (#12909)

# Description
As @YizhePKU pointed out, the [Rust API
guidelines](https://rust-lang.github.io/api-guidelines/interoperability.html#generic-readerwriter-functions-take-r-read-and-w-write-by-value-c-rw-value)
recommend that generic functions take readers and writers by value and
not by reference. This PR changes `copy_with_interupt` and few other
places to take owned `Read` and `Write` instead of mutable references.

crates/nu-command/src/filesystem/save.rs

@@ -508,7 +508,7 @@ fn get_files(
 }
 
 fn stream_to_file(
-    mut source: impl Read,
+    source: impl Read,
     known_size: Option<u64>,
     ctrlc: Option<Arc<AtomicBool>>,
     mut file: File,
@@ -555,7 +555,7 @@ fn stream_to_file(
             Ok(())
         }
     } else {
-        copy_with_interrupt(&mut source, &mut file, span, ctrlc.as_deref())?;
+        copy_with_interrupt(source, file, span, ctrlc.as_deref())?;
         Ok(())
     }
 }