ensure that when nu evaluates files, it allows early returns (#7415)

# Description

Fixes #7301.

# User-Facing Changes

`return` can now be used in scripts without explicit `def main`.

# Tests + Formatting

Don't forget to add tests that cover your changes. (I'm not sure how to
test this.)

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-cli/src/repl.rs

@@ -145,6 +145,7 @@ pub fn evaluate_repl(
             s.item.as_bytes(),
             &format!("entry #{entry_num}"),
             PipelineData::empty(),
+            false,
         );
         engine_state.merge_env(stack, get_guaranteed_cwd(engine_state, stack))?;
     }
@@ -472,6 +473,7 @@ pub fn evaluate_repl(
                         s.as_bytes(),
                         &format!("entry #{entry_num}"),
                         PipelineData::empty(),
+                        false,
                     );
                 }
                 let cmd_duration = start_time.elapsed();