OZG-4527 Use CSS dark mode detection

alfa-client/apps/alfa/src/styles/abstracts/_variables.scss

@@ -25,6 +25,7 @@
 
 $grey: #777;
 $greyLight: rgba(0, 0, 0, 0.08);
+$darkModeGreyLight: rgba(255, 255, 255, 0.6);
 
 $background: #fafafa;
 $dark-background: #303030;

alfa-client/libs/vorgang-detail/src/lib/aktenzeichen-edit-dialog/aktenzeichen-edit-dialog.component.scss

@@ -21,15 +21,11 @@
 
 .az_icon {
 	grid-area: az_icon;
-	color: #c2c2c2;
+	color: $darkModeGreyLight;
 	margin-top: 12px;
 
 	&--active {
 		color: black;
-
-		&--dark-mode {
-			color: #c2c2c2;
-		}
 	}
 }
 
@@ -61,3 +57,9 @@ mat-icon {
 mat-dialog-content {
 	padding-top: 0.5rem !important;
 }
+
+:host-context(.dark) {
+	.az_icon {
+		color: $darkModeGreyLight;
+	}
+}
\ No newline at end of file

alfa-client/libs/vorgang-detail/src/lib/aktenzeichen-edit-dialog/aktenzeichen-edit-dialog.component.ts

-import { AppService } from '@alfa-client/app-shared';
 import { COMMAND_ERROR_MESSAGES, CommandResource, hasError, isSuccessfulDone } from '@alfa-client/command-shared';
 import { StateResource, createEmptyStateResource, hasContent, isClipboardReadSupported } from '@alfa-client/tech-shared';
 import { SnackBarService } from '@alfa-client/ui';
@@ -21,7 +20,6 @@ export class AktenzeichenEditDialogComponent implements OnInit {
 	vorgang: VorgangWithEingangResource;
 
 	setAktenzeichenPending$: Observable<StateResource<CommandResource>> = of(createEmptyStateResource<CommandResource>());
-	darkMode$: Observable<boolean>;
 	hasAktenzeichen$: Observable<boolean>;
 	isPasteSupported = false;
 
@@ -31,7 +29,6 @@ export class AktenzeichenEditDialogComponent implements OnInit {
 		public formService: AktenzeichenEditDialogFormservice,
 		private readonly snackbarService: SnackBarService,
 		private readonly vorgangService: VorgangService,
-		private appService: AppService,
 		public dialogRef: MatDialogRef<AktenzeichenEditDialogComponent>,
 		@Inject(MAT_DIALOG_DATA) public data: AktenzeichenEditDialogData,
 	) {
@@ -44,7 +41,6 @@ export class AktenzeichenEditDialogComponent implements OnInit {
 		this.hasAktenzeichen$ = this.formService.valueChanges()
 		.pipe(startWith(this.vorgang.aktenzeichen))
 		.pipe(map(hasContent));
-		this.darkMode$ = this.appService.getDarkMode();
 	}
 
 	public onCancel(): void {