[Refactor] Remove duplication in git latest tag retrieval

[gonzaloriestra]

WHY are these changes introduced?

The logic for executing git describe --tags --abbrev=0 and trimming the output was duplicated in getLatestTagFromDirectory and getLatestTag within packages/cli-kit/src/public/node/git.ts. Centralizing this logic improves maintainability.

WHAT is this pull request doing?

Refactors getLatestTagFromDirectory to call the existing getLatestTag helper function, removing the duplicated command execution.

How to test your changes?

You can verify the git tag retrieval logic continues to work by running the unit tests for the git module:

pnpm --filter @shopify/cli-kit vitest run src/public/node/git.test.ts

Duplicate check

I performed a manual check using git log since the gh tool was unavailable.
Closest prior PRs considered:

• 311ee45f7 [Refactor] Extract shared execution environment logic in system.ts: Refactors system.ts to extract environment logic; different subsystem.
• 088a35a45 [Refactor] Consolidate command execution in system.ts: Consolidates logic in system.ts; different subsystem.
• 8fbf32490 [Refactor] Fix incorrect Promise.all usage in app preDeployValidation: Fixes an async anti-pattern in app.ts; different technique and subsystem.

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 12497117072717296991 started by @gonzaloriestra

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