Improved error output concerning org.freedesktop.Sdk

[BeverlyCode]

Checklist

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Suggestion

o@o:~/Desktop$ flatpak-builder build-dir com.voxdsp.Snowboarder.yaml
error: org.freedesktop.Sdk/x86_64/23.08 not installed
Failed to init: Unable to find sdk org.freedesktop.Sdk version 23.08

This is quite confusing to workout how to install org.freedesktop.Sdk/x86_64/23.08 I had to Google and find this page: https://gitlab.com/freedesktop-sdk/freedesktop-sdk

Where I discovered the solution was:
flatpak install flathub org.freedesktop.Sdk/x86_64/23.08

I would suggest just directly giving the user the solution in the program output, so just suggest to use flatpak install the more explicit the better.

Thanks!

(might seem obvious to existing flatpak nerds 🤓, but not nerdy me! )

[TingPing]

The nice way to do it is flatpak-builder --install-deps-from=flathub build-dir com.voxdsp.Snowboarder.yaml.

It could be possible that when missing we search enabled repos for it.

[BeverlyCode]

The nice way to do it is flatpak-builder --install-deps-from=flathub build-dir com.voxdsp.Snowboarder.yaml.

It could be possible that when missing we search enabled repos for it.

Ah I see okay, thank you I will make note of this as I plan to write a tutorial for new flathub publishers.