fix: enable screen reader to read file upload desc and error (#2683)

Author: andyl309

src/file-uploader/file-uploader.component.ts

@@ -21,7 +21,7 @@ const noop = () => { };
 	template: `
 		<ng-container *ngIf="!skeleton; else skeletonTemplate">
 			<label [for]="fileUploaderId" class="cds--file--label">{{title}}</label>
-			<p class="cds--label-description">{{description}}</p>
+			<p class="cds--label-description" role="alert">{{description}}</p>
 			<div class="cds--file">
 				<label
 					*ngIf="drop"

src/file-uploader/file.component.ts

@@ -47,7 +47,7 @@ import { FileItem } from "./file-item.interface";
 				[ariaLabel]="translations.CHECKMARK">
 			</svg>
 		</span>
-		<div class="cds--form-requirement" *ngIf="fileItem.invalid">
+		<div class="cds--form-requirement" role="alert" *ngIf="fileItem.invalid">
 			<div class="cds--form-requirement__title">{{fileItem.invalidTitle}}</div>
 			<p class="cds--form-requirement__supplement">{{fileItem.invalidText}}</p>
 		</div>