fix(ecstore): keep the clone-safety assertion without a redundant clone

clippy 1.98 (-D warnings) flags `marked.clone()` at the test's last use
of `marked` as a redundant clone, which turned `cargo clippy --tests`
red on release since #7668 and blocks every PR lane that runs it.
Bind the clone to a variable first so the test still proves both that
the original marker survives cloning and that the clone carries it.

crates/ecstore/src/disk/error.rs

@@ -865,8 +865,9 @@ mod tests {
             io::ErrorKind::PermissionDenied,
             "staging rejected",
         )));
+        let cloned = marked.clone();
         assert!(marked.is_conditional_file_not_committed());
-        assert!(marked.clone().is_conditional_file_not_committed());
+        assert!(cloned.is_conditional_file_not_committed());
         assert!(!DiskError::Timeout.is_conditional_file_not_committed());
         assert!(
             !DiskError::Io(io::Error::new(io::ErrorKind::PermissionDenied, "rename rejected"))