Remove restriction on sprint poker scale length

[acressall]

Currently when a user creates a custom scale they are limited to two characters.

A user has requested a template for "delegation" which uses words on poker cards. It seems like a great use case for sprint poker, but the user is unable to create a custom template for it with this restriction.

[acressall]

Also came up in this conversation https://parabol.slack.com/archives/C4JAUUZ9P/p1654731721948019

[acressall]

A user requests:

In planning poker, I can't add 0.5 or 0,5 value