Avoid panic when pipe a variable to a custom command which have recursive call (#12491)

# Description
Fixes: #11351

And comment here is also fixed:
https://github.com/nushell/nushell/issues/11351#issuecomment-1996191537

The panic can happened if we pipe a variable to a custom command which
recursively called itself inside another block.

TBH, I think I figure out how it works to panic, but I'm not sure if
there is a potention issue if nushell don't mutate a block in such case.

# User-Facing Changes
Nan

# Tests + Formatting
Done

# After Submitting
Done

---------

Co-authored-by: Stefan Holderbach <sholderbach@users.noreply.github.com>

crates/nu-parser/src/parser.rs

@@ -6289,7 +6289,19 @@ pub fn parse(
         // panic (again, in theory, this shouldn't be possible)
         let block = working_set.get_block(block_id);
         let block_captures_empty = block.captures.is_empty();
-        if !captures.is_empty() && block_captures_empty {
+        // need to check block_id >= working_set.permanent_state.num_blocks()
+        // to avoid mutate a block that is in the permanent state.
+        // this can happened if user defines a function with recursive call
+        // and pipe a variable to the command, e.g:
+        // def px [] { if true { 42 } else { px } };    # the block px is saved in permanent state.
+        // let x = 3
+        // $x | px
+        // If we don't guard for `block_id`, it will change captures of `px`, which is
+        // already saved in permanent state
+        if !captures.is_empty()
+            && block_captures_empty
+            && block_id >= working_set.permanent_state.num_blocks()
+        {
             let block = working_set.get_block_mut(block_id);
             block.captures = captures.into_iter().map(|(var_id, _)| var_id).collect();
         }