Remove JetBrains Space from Dart package repositories as a service se…

…ction in custom-package-repositories (#6173)

Given JetBrains Space's pivot to
[SpaceCode](https://blog.jetbrains.com/space/2024/05/27/the-future-of-space/),
which will not include package management functionality as confirmed in
the [official migration
documentation](https://www.jetbrains.com/help/space/migrate-from-space-to-spacecode.html#what-will-not-stay-in-spacecode),
I think SpaceCode should no longer be recommended for teams or projects
that require integrated package management solutions.

src/content/tools/pub/custom-package-repositories.md

@@ -215,10 +215,6 @@ your own custom package repository:
 <li>
   <img src="/assets/img/tools/proget.svg" class="list-image" alt="Inedo ProGet logo">
   <a href="https://docs.inedo.com/docs/proget/feeds/pub"><b>Inedo ProGet</b></a>
-</li>  
-<li>
-  <img src="/assets/img/tools/jetbrains-space.svg" class="list-image" alt="JetBrains Space logo">
-  <a href="https://www.jetbrains.com/help/space/dart-package-repository.html"><b>JetBrains Space</b></a>
 </li>
 <li>
   <img src="/assets/img/tools/jfrog.svg" class="list-image" alt="JFrog logo">