chore: update nvmrc to 22.21.1 to match what we deploy with (#5185)

<!-- Describe the problem and your solution --> 

<!-- Issue ticket number and link (if applicable) -->

<!-- Testing instructions (skip if just adding/editing providers) -->

<!-- Summary by @propel-code-bot -->

---

**Align `.nvmrc` with deployment Node version**

Updates `.nvmrc` to specify Node `22.21.1`, aligning local development
environments with the deployed runtime. Helps keep developer tooling and
deployment targets consistent.

<details>
<summary><strong>Key Changes</strong></summary>

• Updated `.nvmrc` from Node `22.17.1` to `22.21.1`

</details>

<details>
<summary><strong>Affected Areas</strong></summary>

• .nvmrc

</details>

---
*This summary was automatically generated by @propel-code-bot*

Author: rossmcewan

.nvmrc

@@ -1 +1 @@
-22.17.1
+22.21.1