TypeScript fixes for MediaSettings (Dash-Industry-Forum#4761)

* update type declaration for MediaSettings

* fix

* allow value and id as optional elements in DescriptorType

Author: stschr

index.d.ts

@@ -758,9 +758,9 @@ declare namespace dashjs {
         dvbFontFamily?: string;
         dvbMimeType?: string;
         dvbUrl?: string;
-        id: string;
+        id?: string;
         schemeIdUri: string;
-        value: string;
+        value?: string;
     }
 
     export interface Event {
@@ -2770,11 +2770,11 @@ declare namespace dashjs {
     }
 
     export interface MediaSettings {
-        accessibility?: any;
-        audioChannelConfiguration?: any[];
-        lang?: string;
-        role?: string;
-        viewpoint?: any;
+        accessibility?: DescriptorType | string;
+        audioChannelConfiguration?: DescriptorType | string;
+        lang?: RegExp | string;
+        role?: DescriptorType | string;
+        viewpoint?: DescriptorType | string;
     }
 
     export class serviceDescriptions {