refactor(functions/v2/imagemagick): migrate from gm to sharp

[angelcaamal]

Description

Fixes Internal: b/503435756

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Checklist

• I have followed guidelines from CONTRIBUTING.MD and Samples Style Guide
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[gemini-code-assist]

Code Review

This pull request migrates the image processing logic from the gm library to sharp, updating dependencies and test configurations accordingly. The review feedback identifies a potential resource leak where temporary files are not deleted if an error occurs during processing; it is recommended to use a try...finally block to ensure cleanup.

[gemini-code-assist]

Temporary files created in the /tmp directory should be deleted even if an error occurs during processing. Currently, if sharp or upload fails, the unlink calls are skipped, which can lead to memory exhaustion in the Cloud Function environment. Wrapping the processing logic in a try...finally block ensures cleanup.

  try {
    try {
      await sharp(tempLocalPath).blur(16).toFile(tempLocalBlurredPath);
      console.log('Blurred image: ' + file.name);
    } catch (err) {
      console.error('Failed to blur image.', err);
      throw err;
    }

    // Upload result to a different bucket, to avoid re-triggering this function.
    const blurredBucket = storage.bucket(blurredBucketName);

    // Upload the Blurred image back into the bucket.
    const gcsPath = 'gs://' + blurredBucketName + '/' + file.name;
    try {
      await blurredBucket.upload(tempLocalBlurredPath, {destination: file.name});
      console.log('Uploaded blurred image to: ' + gcsPath);
    } catch (err) {
      throw new Error('Unable to upload blurred image to ' + gcsPath + ': ' + err);
    }
  } finally {
    // Delete the temporary files.
    await Promise.allSettled([
      fs.unlink(tempLocalPath),
      fs.unlink(tempLocalBlurredPath),
    ]);
  }