rope: Prevent stack overflows by bumping rayon stack sizes (#41397)

Thread stacks in rust by default have 2 megabytes of stack which for
sumtrees (or ropes in this case) can easily be exceeded depending on the
workload.

Release Notes:

- Fixed stack overflows when constructing large ropes

crates/cli/src/main.rs

@@ -358,6 +358,7 @@ fn main() -> Result<()> {
 
     rayon::ThreadPoolBuilder::new()
         .num_threads(4)
+        .stack_size(10 * 1024 * 1024)
         .thread_name(|ix| format!("RayonWorker{}", ix))
         .build_global()
         .unwrap();