fix: added ui auth rules to the backend model

[saptarshi-datazip]

Description

Added the authentication rules (like password needs to be 6 char length). This doesnot allow user to create credentials that fails in the UI.

If this is breaking maybe we can restore the backend and remove the checks in the frontend ui. ( like if some old user created credentials using curl command and logins using that. it will now fail as the backend will only not allow the login)

Fixes #303

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• [maybe] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Ran with and without the changes and checked the edge case of 6 length password.
Not explicitly tested for username length and other conditions.

Screenshots or Recordings

Before changes:

After changes:

Related PR's (If Any):