chore: Allow LavaMoat packages in age gate (#3845)

Allow LavaMoat packages published outside of the org scope in the age
gate.

Fixes Dependabot not being able to bump certain LavaMoat packages.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Configuration-only change to dependency installation policy; it
slightly broadens which packages can bypass the age gate but does not
change runtime application logic.
> 
> **Overview**
> Updates Yarn's `npmPreapprovedPackages` allowlist to include unscoped
LavaMoat packages (`lavamoat`, `lavamoat-core`, `lavamoat-tofu`),
letting them bypass the `npmMinimalAgeGate` publish-age restriction.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
060f88b. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: FrederikBolding

.yarnrc.yml

@@ -30,3 +30,6 @@ npmPreapprovedPackages:
   - '@metamask/*'
   - '@metamask-previews/*'
   - '@lavamoat/*'
+  - 'lavamoat'
+  - 'lavamoat-core'
+  - 'lavamoat-tofu'