Split Checkout: add error message when no shipping methods are available to the customer

[jibees]

What? Why?

Closes #9145
This adds a flash error message when no available shippings methods:

What should we test?

No shipping methods can occurs either:

• hub didn't configure any shipping methods
• no shipping methods are available due to tag rules

Release notes

Changelog Category: User facing changes

[mkllnk]

This is good but needs a conflict resolution. Moving to dev.

[drummer83]

Hi @jibees,
Thanks for this one! 💪

Before this PR

I have first tested before staging your PR to reproduce the issue. You can see the useless error message in the screen capture below.

All shipping methods are set to backoffice only

Split checkout:

Legacy checkout:

Shipping method is hidden through tag rules:

Split checkout:

Legacy checkout:

Shipping method is shown through tag rules:

Split checkout:

Legacy checkout:

After this PR

All shipping methods are set to backoffice only

Split checkout:

Legacy checkout:
unchanged

Shipping method is hidden through tag rules:

Split checkout:

Legacy checkout:
unchanged

Shipping method is shown through tag rules:

Split checkout:
unchanged

Legacy checkout:
unchanged

I have nothing else to ask for. This one is ready to go! 🎆

[mkllnk]

I resolved a conflict and will merge once specs pass.

[mkllnk]

It looks like we have a related spec failure now. Back to In Dev.

[jibees]

It looks like we have a related spec failure now. Back to In Dev.

Seems to be unrelated to this branch, as it also occurs in master: https://github.com/openfoodfoundation/openfoodnetwork/runs/8240457288?check_suite_focus=true

Since, merging #9631

I'll open an issue, and try to resolve it.

[sigmundpetersen]

This is probably good to go then?