fix type of nickname and character_class

[hrk4649]

Please check if the PR fulfills these requirements:

• [x] The commit message follows our guidelines.
• For bug fixes and features:
  • [x] You tested the changes.

Related issue (if applicable): #

What kind of change does this PR introduce?

Correction of variable type.

Does this PR introduce a breaking change?

No.

New feature or change

What is the current behavior?

The program stops and the debugger says "Trying to assign value of type 'LineEdit' to a variable of type 'Label'.".

What is the new behavior?

The program shows UserProfile.tscn.

Other information

[NathanLovato]

Thanks!