Update Rust crate config to 0.15.12 (#2449)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [config](https://redirect.github.com/rust-cli/config-rs) |
workspace.dependencies | patch | `0.15.11` -> `0.15.12` |

---

### Release Notes

<details>
<summary>rust-cli/config-rs (config)</summary>

###
[`v0.15.12`](https://redirect.github.com/rust-cli/config-rs/blob/HEAD/CHANGELOG.md#01512---2025-07-08)

[Compare
Source](https://redirect.github.com/rust-cli/config-rs/compare/v0.15.11...v0.15.12)

##### Performance

- Upgrade to `toml` v0.9

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "after 8pm,before 6am" in timezone
America/Los_Angeles, Automerge - "after 8pm,before 6am" in timezone
America/Los_Angeles.

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR is behind base branch, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

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Author: nextest-bot

Cargo.lock

@@ -40,7 +40,7 @@ cfg-if = "1.0.1"
 color-eyre = "0.6.5"
 # config's "preserve_order" feature is needed for preserving the order of
 # setup scripts in .config/nextest.toml.
-config = { version = "0.15.11", default-features = false, features = [
+config = { version = "0.15.12", default-features = false, features = [
     "toml",
     "preserve_order",
 ] }

Cargo.toml

@@ -40,7 +40,6 @@ smallvec = { version = "1.15.1", default-features = false, features = ["const_ge
 target-spec = { version = "3.4.2", default-features = false, features = ["custom", "summaries"] }
 target-spec-miette = { version = "0.4.4", default-features = false, features = ["fixtures"] }
 tokio = { version = "1.46.1", features = ["fs", "io-std", "io-util", "macros", "process", "rt-multi-thread", "signal", "sync", "time", "tracing"] }
-toml = { version = "0.8.23", features = ["preserve_order"] }
 toml_edit = { version = "0.22.27", features = ["serde"] }
 tracing-core = { version = "0.1.33" }
 tracing-subscriber = { version = "0.3.19", default-features = false, features = ["fmt", "tracing-log"] }