fix: prevent trashing of trashed assets (#10028)

* fix: prevent trashing of trashed assets

Motivation
----------
This will improve user experience by hiding a pointless action.

You can not trash a trashed asset again. It won't get any trashier than it already is.

How to test
-----------
1. Visit route `/trash`
2. Click on an asset
3. Press "Delete" on your keyboard
4. Nothing happens
5. Try to find the trash button in the top right
6. You can't find it

* refactor: follow @michelheusschen's review

See:
https://github.com/immich-app/immich/pull/10028#pullrequestreview-2105296755

* refactor:  follow @michelheusschen's 2nd review

See: https://github.com/immich-app/immich/pull/10028#discussion_r1632057833

web/src/lib/components/asset-viewer/delete-button.spec.ts

@@ -0,0 +1,34 @@
+import { type AssetResponseDto } from '@immich/sdk';
+
+import { assetFactory } from '@test-data/factories/asset-factory';
+import '@testing-library/jest-dom';
+import { render } from '@testing-library/svelte';
+import DeleteButton from './delete-button.svelte';
+
+let asset: AssetResponseDto;
+
+describe('DeleteButton component', () => {
+  describe('given an asset which is not trashed yet', () => {
+    beforeEach(() => {
+      asset = assetFactory.build({ isTrashed: false });
+    });
+
+    it('displays a button to move the asset to the trash bin', () => {
+      const { getByTitle, queryByTitle } = render(DeleteButton, { asset });
+      expect(getByTitle('delete')).toBeInTheDocument();
+      expect(queryByTitle('deletePermanently')).toBeNull();
+    });
+  });
+
+  describe('but if the asset is already trashed', () => {
+    beforeEach(() => {
+      asset = assetFactory.build({ isTrashed: true });
+    });
+
+    it('displays a button to permanently delete the asset', () => {
+      const { getByTitle, queryByTitle } = render(DeleteButton, { asset });
+      expect(getByTitle('permanently_delete')).toBeInTheDocument();
+      expect(queryByTitle('delete')).toBeNull();
+    });
+  });
+});