Fix screen generation bug when using specific inputs

[LuisFSegalla]

I recently had some issues when running odin-fastcs against the xspress detector code. The problem seem to consist of the screen generation not handling very well one of the plugins being called "xspress-list" (see error log below)

ValidationError: 1 validation error for Group
name
String should match pattern '^([A-Z][a-z0-9])$'
[type=string_pattern_mismatch, input_value='XSPRESS-LIST', input_type=str]
For further information visit
https://errors.pydantic.dev/2.8/v/string_pattern_mismatch

I don't know how much this can be made more generic, as if using a - character could cause some issues with the PV naming standards we have at Diamond.