Fix - Critical issue when the publishable key is empty in live mode for recurring payment

[riteelama]

All Submissions:

• Have you followed the Everest Forms Contributing guideline?
• Does your code follow the WordPress' coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

This pull request addresses a critical issue in the Everest Forms Stripe integration that arises when test publishable key and test secret key are set without enabling test mode. Specifically, when users attempt to enable recurring payments from the form settings under these conditions, it leads to an error that affects the functionality of the integration.

Closes # .

How to test the changes in this Pull Request:

1. Enable the Everest Form Stripe Addons
2. Go to Everest Forms Settings > Payments > Stripe Settings
3. Enter the Test Publishable Key, Test Secret Key and disable Enable test Mode
4. Now go to Form settings > Payments
5. Enable Stripe Recurring Payment and click on Save button
6. Now try to drag and drop the credit card field.
7. A pop up must appear to show the message and button must redirect to the setup page.

PR Dependency

Types of changes:

• Bug fix (non-breaking change which fixes an issue)
• Enhancement (modification of the currently available functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you successfully ran tests with your changes locally?
• Have you updated the documentation accordingly?

Changelog entry

Fix - Critical issue when the publishable key is empty in live mode for recurring payment.