fix: slack notification

[Arjxm]

This pull request includes several changes to the index.js file to improve the deployment notification process and update API endpoints. The most important changes include updating URLs, adding a function to extract contract data, validating deployment data, and handling deployment failures more robustly.

API endpoint updates:

• Updated the sandbox API URL from https://api.dev.buildbear.io/v1/buildbear-sandbox to https://api.buildbear.io/v1/buildbear-sandbox in the createNode function.
• Updated the deployment notification API URL from https://api.dev.buildbear.io/ci/deployment-notification to https://api.buildbear.io/ci/deployment-notification in the sendNotificationToBackend function.

Deployment data extraction and validation:

• Added the extractContractData function to extract relevant contract data for notification.
• Added the validateDeployment function to validate if deployment was successful by checking for valid transactions.

Enhanced error handling:

• Modified the sendNotificationToBackend function to process deployment data, validate deployment success, and update the status and summary accordingly. If validation fails, the status is set to "failed" and the summary is updated with the validation message. Additionally, if the status is changed to "failed", the GitHub Action is set to fail.