[tag explorer] don't use `All` as label

[eh-am]

We should make a distinction between a selected tag and "all", in the latter case, don't treat that as a normal label.

Here's an example on how it's treated as a normal label and when you go to "Single" it uses All as a label, which doesn't exist. https://user-images.githubusercontent.com/6951209/183476860-e3f3d429-86b2-4e74-ad8e-ab009aa8eeb1.mp4