[Site Design Revamp] Randomize order of designs for categories

[antonis]

Fixes #16506

Depends on: #16510

Description

This PR randomises the order of the designs shown for categories. The recommended designs area does not use random ordering unless the Blog category fallback is recommended.

To test:

To fully test this PR the group field (ref D80005) and recommended designs (ref D80579) should be available on the backend or sandbox.

Vertical with recommendations selected

1. Start the site creation flow
2. Select on of the six initial/default verticals that have associated recommended designs
3. Verify that the recommended designs are suggested at the top
4. Verify that the recommended designs are not shuffled (keep the api order)
5. Verify that the order of the designs in the other categories is random

Vertical selection skipped

1. Start the site creation flow
2. Skip the vertical selection
3. Verify that the blog category is recommended at the top
4. Verify that the order of the designs in the all categories is random

Vertical has no recommendations

1. Start the site creation flow
2. Select a vertical that is not one of the initial/default verticals or enter a custom vertical
3. Verify that the blog category is recommended at the top
4. Verify that the order of the designs in the all categories is random

Regression

1. Tap the ➕ button on the My site screen
2. Select Site page
3. Verify that the order of the layouts unchanged (not random)

Regression Notes

1. Potential unintended areas of impact
   Page layout picker

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   Relied on existing test

3. What automated tests I added (or what prevented me from doing so)
   Extended tests in SiteDesignRecommendationProviderTest

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

You can trigger optional UI/connected tests for these changes by visiting CircleCI here.

[peril-wordpress-mobile]

You can test the changes on this Pull Request by downloading the APKs:

• Jetpack-pr-16531-build-123349.apk

• WordPress-pr-16531-build-123349.apk

[ovitrif]

Great work, it works as expected 🎉