chore: add preffer readonly lint rule to test fix

[distante]

1. Call npx nx run-many --target=lint --quiet --skip-nx-cache --all and see how it fails.
2. Call npx nx run-many --target=lint --quiet --skip-nx-cache --all --fix, it passes.
3. Call again npx nx run-many --target=lint --quiet --skip-nx-cache --all it still fails

Extra info, I do not use nx globally, that is why I always call npx nx.

When nx is installed globally (I just install it, together with yarn so I could call nx report, --fix changes the files.!

[nx-cloud]

☁️ Nx Cloud Report

CI ran the following commands for commit cc2f2c4. Click to see the status, the terminal output, and the build insights.

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🟥 Failed Commands
nx affected:lint --base 4ce39df28b05eb777dc9979968d55d8f22475ab0 --parallel

✅ Successfully ran 3 targets

• nx affected:test --base 4ce39df28b05eb777dc9979968d55d8f22475ab0 --parallel -- --ci --code-coverage
• nx affected:e2e --base 4ce39df28b05eb777dc9979968d55d8f22475ab0 --configuration production --parallel false -- --headless
• nx affected:build --base 4ce39df28b05eb777dc9979968d55d8f22475ab0 --parallel --configuration production

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