ignore_unavailable is not defined in rollupSearch

src/platform/plugins/shared/data/server/search/strategies/ese_search/ese_search_strategy.test.ts

@@ -314,7 +314,9 @@ describe('ES search strategy', () => {
         expect(mockRollupSearchCaller).toHaveBeenCalledWith(
           {
             index: 'foo-程',
-            ignore_unavailable: true,
+            querystring: {
+              ignore_unavailable: true,
+            },
             max_concurrent_shard_requests: undefined,
             timeout: '100ms',
             track_total_hits: true,

src/platform/plugins/shared/data/server/search/strategies/ese_search/ese_search_strategy.ts

@@ -166,12 +166,20 @@ export const enhancedEsSearchStrategyProvider = (
       throw new KbnSearchError(`"params.index" is required when performing a rollup search`, 400);
     }
 
+    // eslint-disable-next-line @typescript-eslint/naming-convention
+    const { ignore_unavailable, ...params } = {
+      ...querystring,
+      ...request.params,
+      index: request.params.index,
+    };
+
     try {
       const esResponse = await client.rollup.rollupSearch(
         {
-          ...querystring,
-          ...request.params,
-          index: request.params.index,
+          ...params,
+          // Not defined in the spec, and the client places it in the body.
+          // This workaround allows us to force it as a query parameter.
+          querystring: { ignore_unavailable },
         },
         {
           signal: options?.abortSignal,