Added a new data service interface to get custom call text, not implemented so this is a no-op.

PiperOrigin-RevId: 828438136

Author: zzzaries

frontend/app/services/data_service_v2/data_service_v2.ts

@@ -255,6 +255,12 @@ export class DataServiceV2 implements DataServiceV2Interface {
     return '';
   }
 
+  getCustomCallText(
+      sessionId: string, moduleName: string, opName: string,
+      programId: string): Observable<string> {
+    return of('');
+  }
+
   // Download by program id is not implemented yet, as the processor is missing
   // hlo proto map by program id.
   downloadHloProto(

frontend/app/services/data_service_v2/data_service_v2_interface.ts

@@ -77,6 +77,10 @@ export interface DataServiceV2Interface {
       programId: string,
       ): string;
 
+  getCustomCallText(
+      sessionId: string, moduleName: string, opName: string,
+      programId: string): Observable<string>;
+
   downloadHloProto(
       sessionId: string,
       moduleName: string,