using a more specfic exception

Author: masseyke

modules/data-streams/src/main/java/org/elasticsearch/datastreams/action/TransportUpdateDataStreamMappingsAction.java

@@ -36,6 +36,7 @@
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -169,7 +170,7 @@ private void updateSingleDataStream(
                                 dataStream.getEffectiveMappings(clusterService.state().metadata().getProject(projectId), indicesService)
                             )
                         );
-                    } catch (Exception e) {
+                    } catch (IOException e) {
                         dataStreamMappingsResponseActionListener.onResponse(
                             new UpdateDataStreamMappingsAction.DataStreamMappingsResponse(
                                 dataStreamName,

server/src/main/java/org/elasticsearch/cluster/metadata/DataStream.java

@@ -423,7 +423,7 @@ public Settings getEffectiveSettings(ProjectMetadata projectMetadata) {
      * @return A JSON CompressedXContent representation of the effective mappings of this data stream
      * @throws Exception
      */
-    public CompressedXContent getEffectiveMappings(ProjectMetadata projectMetadata, IndicesService indicesService) throws Exception {
+    public CompressedXContent getEffectiveMappings(ProjectMetadata projectMetadata, IndicesService indicesService) throws IOException {
         return getEffectiveMappings(projectMetadata, getMatchingIndexTemplate(projectMetadata), mappings, getWriteIndex(), indicesService);
     }