[Refactor] Use .find() in ensureThemeExtensionDevContext

[gonzaloriestra]

WHY are these changes introduced?

The code was using the .filter()[0] pattern to find a specific element in an array. Using .find() is more idiomatic in TypeScript/JavaScript, improves readability, and provides a small performance benefit by short-circuiting once the element is found.

WHAT is this pull request doing?

Refactors the ensureThemeExtensionDevContext function in packages/app/src/cli/services/context.ts to replace the .filter().[0] pattern with .find().

How to test your changes?

CI

Post-release steps

N/A

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add

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PR created automatically by Jules for task 3162748275259681757 started by @gonzaloriestra

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