Variations: Stop generation if there are more than 100 variations to generate

[Ecarrion]

closes: #8489

Why

This PR makes sure to stop the generation process and inform the merchant when there is more than 100 generations to create.

How

• Adde a new GenerationError type with a tooManyVariations case to represent the situation where there are more than 100 variations to create.

• Integrate the error defined above in the ViewModel and in the ViewController to properly inform the merchant via a notice.

Demo

generation-error.mov

Testing Steps

• Create a new variable product.
• Create at least 3 attributes, each with at least 5 options.
• Create the first generic variation. (related Variations: Allow to create all variations from empty states #8534)
• Tap on the "Add Variation" CTA to generate all variations
• See the error presented on the notice.

---

• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[wpmobilebot]

You can test the changes from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr8541-5636c23 on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[ealeksandrov]

Loog good! Added 1 non-blocking improvement suggestion.

[ealeksandrov]

Can't we guard for this overflow early? So we won't actually create a lot of objects before failing? We should be able to quickly count possible combinations by multiplying the amount of options for each attribute.

But I'm not sure if we can easily subtract a number of existing variations - there may be duplicated combinations. Can we subtract just total number of existing variations for pre-generation guard (for a worst case)? And if it <100, we can proceed to existing check to make additional verification of combinations.

[Ecarrion]

I don't think we will hit a performance problem here right now. The plan is to eventually ask core to generate variations so probably not worth spending extra time on performance unless we notice something significant!

[peril-woocommerce]

	Warnings
⚠️	This PR is assigned to a milestone which is closing in less than 2 days Please, make sure to get it merged by then or assign it to a later expiring milestone

Generated by 🚫 dangerJS