fix(admin-ui): rename "Authn" to "Authentication" in menu and page title

[ossdhaval]

Summary:

• The menu label and page title currently display as “Authn” instead of “Authentication”

Steps to Reproduce:

• Navigate to Auth Server → Authn in the left navigation panel.
• Observe the menu label in the sidebar and the page title in the top header.

Actual Behavior:

• Both the sidebar menu and the page header display the shortened term “Authn”.

Expected Behavior:

• Both the sidebar menu and the page header should display the full word Authentication to maintain clarity and consistency.

[duttarnab]

@ossdhava lTUI also uses the same name. I think the term was coined by @nynymike.

[ossdhaval]

I have seen TUI using short-forms to work around its rendering limitations. But in this case, I think TUI can also use the full form. Besides, web front-ends should not follow TUI when it comes to aesthetics and usability. So, I still think admin-ui should use Authentication instead of Authn.

Re: I think the term was coined by @nynymike..
I think he'll disagree. 😉
It is a widely used short-form for authentication. For example, in webauthn.