Enatega Customer Application: App isn't allowing a one-letter first name during sign-up and change Validation message accordingly

Is your feature request related to a problem? Please describe.

App isn't allowing a one-letter first name during sign-up.
Consider special cases where a single letter might be valid (e.g., some East Asian names).

Also change Validation message accordingly, under the first name field if user enters a single letter its showing a validation message Invalid First Name ! which isn't relevant to the field.

Describe the solution you'd like
The app is designed to allow one-letter first names (some cultures do have single-letter names, initials, or mononyms).
The business logic intentionally permits it for inclusivity.

No file or test entry point is named. Start by locating the customer application's sign-up first-name validation and its displayed error message; verify that a one-letter first name is accepted and that any remaining validation message accurately describes the field.

Written by the indexing model from the issue text.