chore: remove once_cell dependency from multiple crates (#4154)

This commit removes the `once_cell` dependency from `Cargo.toml` files
in the `codex-rs` and `apply-patch` directories, replacing its usage
with `std::sync::LazyLock` and `std::sync::OnceLock` where applicable.
This change simplifies the dependency tree and utilizes standard library
features for lazy initialization.

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codex-rs/apply-patch/Cargo.toml

@@ -20,7 +20,6 @@ similar = { workspace = true }
 thiserror = { workspace = true }
 tree-sitter = { workspace = true }
 tree-sitter-bash = { workspace = true }
-once_cell = { workspace = true }
 
 [dev-dependencies]
 assert_cmd = { workspace = true }