Discussion can be created with whitespace-only name

Description

When creating a discussion, the Name field accepts whitespace-only input (spaces/tabs).
Submitting the form with such input successfully creates a discussion with an effectively empty name.
This results in unnamed discussions appearing in the sidebar, which can be confusing and hard to manage.
see 👇

Steps to reproduce

1. Click + → Create discussion
2. Select a Parent channel or team
3. In the Name field, enter only spaces (e.g. " ")
4. Click Create

Expected behavior

1. The discussion should not be created if the Name contains only whitespace.
2. The Name field should be validated after trimming whitespace and show an error (similar to an empty value).

Actual behavior

1.The discussion is created successfully.
2. The discussion appears in the sidebar without a visible name.

Why this matters

1. The Name field is required, but whitespace-only input bypasses validation.
2. This can lead to:
   i) Unidentifiable discussion rooms
   ii) Confusing navigation for users and admins
   iii) Potential moderation and accessibility issues

Environment

1. Rocket.Chat Web
2. Tested locally
3. Browser: Chrome
4. OS: Any

Evidence

https://github.com/user-attachments/assets/c7696aad-7474-44bb-9397-0443496998e4

Start by reproducing the issue in Rocket.Chat Web through the Create discussion form, using spaces or tabs in the Name field. Trace the existing required-name validation and make sure whitespace-only input shows an error and does not create a discussion; confirm the behavior against the listed reproduction steps.