As a developer I wanted to set proper content types validator for contenttypelist attribute type in contentlist block

Steps:

1. Create a CT with a digit in the identifier.
2. Edit a Landing Page.
3. Add Content List block.
4. Open Settings.
5. Fill mandatory fields.
6. Select the CT from step 1 in "Content Types to be displayed" dropdown.
7. Try to submit.

Actual: Validation error is displayed "Choose at least one content type".
Expected: CTs with digits are correctly validated.