Fix bugs related to mesh loading and short links

[daniel-wer]

This PR fixes three issues.

1. Fixed a bug where loaded meshes were not encoded in the sharing link.
2. Fixed a bug where meshes (or chunks of them) were always colored white, if they were loaded while the corresponding segmentation layer was disabled.
3. Fixed a race condition when opening a short link, that would sometimes lead to an error toast.

URL of deployed dev instance (used for testing):

• https://___.webknossos.xyz

Steps to test:

• Open the dev tools
• Load a mesh, disable the segmentation layer and copy the sharing link. When opening the sharing link, the mesh should be loaded and it should have the corresponding segment's color (not white!).
• Check the network tab of the dev tools after opening a short link. There should only be a single request to api/shortLinks/byKey/.... Before, there was a second request to /api/shortLinks/byKey/https: which led to an error toast, sometimes.

Issues:

• fixes Mesh chunks loaded while the segmentation layer is disabled are always white #7496

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(Please delete unneeded items, merge only when none are left open)

• Updated changelog
• Removed dev-only changes like prints and application.conf edits
• Considered common edge cases

[philippotto]

Awesome, thanks for fixing these 👍 Works well!