[turbopack] Use bail! instead of panic! for duplicate module ident error (#91636)
### What?
In `turbopack/crates/turbopack-core/src/module_graph/mod.rs`, the
`#[cfg(debug_assertions)]` duplicate module ident detection block inside
`SingleModuleGraph::new_inner` called `panic!` when duplicates were
found.
### Why?
`panic!` terminates the process hard, bypassing the normal
error-handling chain. The enclosing function `new_inner` already returns
`anyhow::Result<Vc<Self>>`, and `bail!` is already imported and used
elsewhere in the same file. Using `bail!` converts this into a
propagatable error, consistent with the rest of the error-handling
idioms in the module.
### How?
Single-line change: replace `panic!(...)` with `bail!(...)` at the
duplicate module detection site. No new imports needed — `bail!` was
already in scope via `use anyhow::{Context, Result, bail};`.
Co-authored-by: Tobias Koppers <sokra@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>