"Assign to All Channels" Button and Simplify "Assigned Channels" Infobox Display

[johannabertils]

Is your feature request related to a problem? Please describe.
In the Vendure Admin UI, managing channels for entities can be unmanageable, especially when there are many channels (e.g., 27 channels for us). Currently, administrators must manually select each channel, and when a entity is assigned to all channels, the infobox lists each one individually, which can be overwhelming and cluttered.

Describe the solution you'd like

1. Add an "Assign to All Channels" button or bulk selection: This would allow administrators to quickly assign an entity to all channels with a single action, streamlining the process and saving time.
2. Simplify the "Assigned Channels" infobox display: When an entity is assigned to all channels, the infobox could display the simplified text "Assigned to all channels" instead of listing each channel separately. This change would provide a cleaner interface and improve usability, and reduce the risk of errors if one channel is accidentally missed.