upgrade: update dependency dart to v3.1.3 (#426)

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This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [dart](https://dart.dev/)
([source](https://togithub.com/dart-lang/sdk)) | patch | `3.1.2` ->
`3.1.3` |

---

### Release Notes

<details>
<summary>dart-lang/sdk (dart)</summary>

### [`v3.1.3`](https://togithub.com/dart-lang/sdk/compare/3.1.2...3.1.3)

[Compare
Source](https://togithub.com/dart-lang/sdk/compare/3.1.2...3.1.3)

</details>

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.tool-versions

@@ -1,2 +1,2 @@
-dart 3.1.2
+dart 3.1.3
 flutter 3.13.5-stable