Fix login button style

[simfeld]

⚠️ “Anmelden mit eCamp” Button in disabled state is extremely faint and hard to see #8271 (comment)

[manuelmeister]

Please use our prefix .ec-
If we change this everywhere, we can do it after the migration.

[simfeld]

Please use our prefix .ec- If we change this everywhere, we can do it after the migration.

Ok, I would like to see this changed because it took me some time to understand that this stands for ecamp instead of some vue-defined classname. Letters are cheap in the days of AI so we should not be thrifty IMO :-)