Adding support for sending request headers in azure core rest request API (#16443)

* Adding support for sending additional headers in azure http requests

* Added session ids in all azure rest calls

* Fixed param name

* Adding default parameter value for request headers

extensions/sql-migration/src/api/utils.ts

@@ -193,3 +193,9 @@ export function decorate(decorator: (fn: Function, key: string) => Function): Fu
 		descriptor[fnKey] = decorator(fn, key);
 	};
 }
+
+export function getSessionIdHeader(sessionId: string): { [key: string]: string } {
+	return {
+		'SqlMigrationSessionId': sessionId
+	};
+}