[EuiSelectableSitewideTemplate][Fix] Do not show noMatchesMessage if one is provided by consumer

[rshen91]

Summary

Hello team! I'm working on fixing elastic/kibana#151199 and I think this PR addresses the strange behavior.

Please provide me any guidance on the fix and getting it up to library standards. Thank you!

I'm including a video of the strange double no results errors displayed with a slow network:

Screen.Recording.2024-05-14.at.12.56.11.PM.mov

• Add unit test Add cypress test
• Update storybook to provide example

[kibanamachine]

Preview staging links for this PR:

• Docs site: https://eui.elastic.co/pr_7758/
• Storybook: https://eui.elastic.co/pr_7758/storybook

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 58b0c80

History

• 💚 Build #1984 succeeded d7da129
• 💔 Build #1967 failed 6f78520
• 💔 Build #1966 failed 7b68459

[cee-chen]

@rshen91 To be totally honest with you, I don't see how this PR would fix the issue shown in the screencap. The messages aren't the same at all (EUI's default empty message is No results available, the one in the screenshot is No results found, so they're not the same message).

I'm pretty sure what's happening on a slow network is that the SVG image is just taking extra time to load in.

[rshen91]

@cee-chen I think this is the part that's causing the issue in elastic/kibana#151199 since selectable_template_sitewide isn't registering the noMatchesMessage intially? Lmk what you think, I definitely concede I could be misunderstanding.

[cee-chen]

It is registering it via ...rest. Anything that comes in from that spread overrides the preceding props, which in production includes noMatchesMessage.