Validation added at shouldAddToCart prop.

[marcosewbank]

What is the purpose of this pull request?
Add a new validation at the "shouldAddToCart" props of the "BuyButton" component that allows the costumer select the SKU and add the product at the cart directly from any search-result page.

Example: https://nimb.ws/6ACwdq

What problem is this solving?
Without the old validation the value of "shouldAddToCart" props is always false, redirecting the user to the product page.

Example: https://nimb.ws/uM6BZc

How should this be manually tested?
You can test the bug at:
https://miniprix.myvtex.com/femei

and the solution at:
https://addtocart--miniprix.myvtex.com/femei

Screenshots or example usage
How the code was working:
https://i.imgur.com/myupcgZ.png
https://i.imgur.com/pJwQPqo.png

My solution:
https://i.imgur.com/F0ZVWzq.png

[vtex-io-ci-cd]

Hi! I'm VTEX IO CI/CD Bot and I'll be helping you to publish your app! 🤖

Please select which version do you want to release:

• Patch

• Minor

• Major

And then you just need to merge your PR when you are ready! There is no need to create a release commit/tag.

• No thanks, I would rather do it manually 😞

[vtex-io-docs-bot]

Beep boop 🤖

I noticed you didn't make any changes at the docs/ folder

• There's nothing new to document 🤔
• I'll do it later 😞

In order to keep track, I'll create an issue if you decide now is not a good time

• I just updated 🎉🎉

[klzns]

Hi, @marcosewbank thanks for the contribution.

We have this #249 to do what you need.

I'm going to try to merge it next week.

[marcosewbank]

@klzns please close this merge too #224