[P3] Support special characters in workflow step names

[brandonjackson]

Problem:
As raised by @lmac-1 in #product-feedback, non-english users struggle to define names without special characters.

Solution Proposal:
Remove this special character validation function since we treat step names as labels in the yaml now.

[hanna-paasivirta]

If we fix this please let me know as the Apollo logic for filtering special characters will need to be aligned with Lightning.