fix(ci): remove matrix from prepare job to fix fromJson empty input

[cryptodev-2s]

Explanation

The upgrade to action-checkout-and-setup from v2 to v3 (#8047) introduced a fast-path optimization that skips the git checkout when there's a node_modules cache hit. This caused the prepare job's yarn workspaces list command to produce empty output, since the repo was never checked out. Combined with the matrix strategy race condition (3 Node versions racing to set a single job output), fromJson receives an empty string and fails.

Fix by:

• Removing the unnecessary matrix from prepare (package names are identical across Node versions)
• Disabling cache-node-modules so the action always performs the checkout
• Pinning to a single Node version (22.x)

References

• Related to chore(deps): bump MetaMask/action-checkout-and-setup from 2 to 3 #8047

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Low Risk
Low risk CI-only change, but it can affect workflow runtime and caching behavior by disabling node_modules cache and pinning the prepare job to a single Node version.

Overview
Fixes CI workflow flakiness in .github/workflows/lint-build-test.yml by removing the Node version matrix from the prepare job so it produces a single, deterministic child-workspace-package-names output.

Forces a real checkout in prepare by setting cache-node-modules: false and pins prepare to node-version: 22.x, avoiding empty fromJson inputs caused by skipped checkout/output races.

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