[ES 9.0] Remove body workaround (@elastic/ml-ui) (#217221)

## Summary

Follow up to #213375: The latest
version of the ES client fixed the issue
elastic/elasticsearch-js#2584.

We should be able to remove all usages of `// @ts-expect-error
[email protected]
https://github.com/elastic/elasticsearch-js/issues/2584`.

Author: afharo

x-pack/platform/plugins/shared/ml/server/routes/data_frame_analytics.ts

@@ -398,10 +398,7 @@ export function dataFrameAnalyticsRoutes(
       routeGuard.fullLicenseAPIGuard(async ({ mlClient, request, response }) => {
         try {
           const body = await mlClient.explainDataFrameAnalytics(
-            {
-              // @ts-expect-error [email protected] https://github.com/elastic/elasticsearch-js/issues/2584 (_meta)
-              body: request.body,
-            },
+            request.body,
             getAuthorizationHeader(request)
           );
           return response.ok({
@@ -648,8 +645,7 @@ export function dataFrameAnalyticsRoutes(
           const body = await mlClient.updateDataFrameAnalytics(
             {
               id: analyticsId,
-              // @ts-expect-error [email protected] https://github.com/elastic/elasticsearch-js/issues/2584 (_meta)
-              body: request.body,
+              ...request.body,
             },
             getAuthorizationHeader(request)
           );