ESQL does not support cross-cluster search yet; when a CCS pattern is used in a FROM command, the error message is not very clear for the end user

<img width="590" alt="Screenshot 2023-11-27 alle 15 38 02" src="https://github.com/elastic/elasticsearch/assets/459289/5af48932-4a4c-416a-a926-7bd486d282a5">

We should make it more user friendly
x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plugin/ComputeService.java
var concreteIndices = PlannerUtils.planConcreteIndices(physicalPlan);
        QueryPragmas queryPragmas = configuration.pragmas();
        if (concreteIndices.isEmpty()) {
            var computeContext = new ComputeContext(sessionId, List.of(), configuration, null, null);
            runCompute(rootTask, computeContext, coordinatorPlan, listener.map(unused -> collectedPages));
            return;
        }
        QueryBuilder requestFilter = PlannerUtils.requestFilter(dataNodePlan);
        LOGGER.debug("Sending data node plan\n{}\n with filter [{}]", dataNodePlan, requestFilter);
        String[] originalIndices = PlannerUtils.planOriginalIndices(physicalPlan);
        computeTargetNodes(
            rootTask,
            requestFilter,
            concreteIndices,
            originalIndices,
            listener.delegateFailureAndWrap((delegate, targetNodes) -> {
                final ExchangeSourceHandler exchangeSource = exchangeService.createSourceHandler(
                    sessionId,
                    queryPragmas.exchangeBufferSize(),
                    ESQL_THREAD_POOL_NAME
                );
                try (
                    Releasable ignored = exchangeSource::decRef;
                    RefCountingListener requestRefs = new RefCountingListener(delegate.map(unused -> collectedPages))
                ) {
                    final AtomicBoolean cancelled = new AtomicBoolean();
                    
                    exchangeSource.addCompletionListener(requestRefs.acquire());
                    
                    var computeContext = new ComputeContext(sessionId, List.of(), configuration, exchangeSource, null);