VSB-TUO/Refactor: align eager-themes.module.ts with the other customer backports (#1320)

Rebuilds this follow-up on the current customer/vsb-tuo base (which now carries
the final overlay mechanism #1318/#1321 and #1333). Drops the duplicate dspace
eager-theme import (imported once as DSpaceEagerThemeModule and again, unaliased,
as EagerThemeModule) so this file matches the canonical form on TUL/SAV/ZCU-DATA/
ZCU-PUB: dspace eager theme once + custom eager theme once.

The earlier blank-page guard from this branch is intentionally dropped: #1321
removed the ds-app visibility:hidden rule (the overlay is now a purely visual
mask), so the early-return can no longer hide the app, and the other customers
took VSB-TUO's #1321 index.html verbatim. Keeping a guard only here would
re-diverge index.html.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: jr-rk

src/themes/eager-themes.module.ts

@@ -1,6 +1,5 @@
 import { NgModule } from '@angular/core';
 import { EagerThemeModule as DSpaceEagerThemeModule } from './dspace/eager-theme.module';
-import { EagerThemeModule } from './dspace/eager-theme.module';
 import { EagerThemeModule as CustomEagerThemeModule } from './custom/eager-theme.module';
 
 /**
@@ -18,10 +17,6 @@ import { EagerThemeModule as CustomEagerThemeModule } from './custom/eager-theme
 @NgModule({
   imports: [
     DSpaceEagerThemeModule,
-    // Uncomment this because the `untyped-item` theming is not working when it is commented out.
-    // Issue: https://github.com/DSpace/dspace-angular/issues/1897
-    // Useful info in PR: https://github.com/DSpace/dspace-angular/pull/2262#issuecomment-1557146081
-    EagerThemeModule,
     CustomEagerThemeModule,
   ],
 })