fix(metric): use lighter import lookup and correct async response schema

- MetricCsv.createEntity now uses findByNameOrNull instead of
  Entity.getEntityByName with all fields, avoiding a per-row fetch of
  every related field. The CSV row is the source of truth for all
  writable fields anyway.
- importMetricsAsync OpenAPI annotation now declares CSVImportResponse
  (jobId/message) instead of CsvImportResult, matching what
  importCsvInternalAsync actually returns.

Author: RajdeepKushwaha5

openmetadata-service/src/main/java/org/openmetadata/service/jdbi3/MetricRepository.java

@@ -516,12 +516,10 @@ protected void createEntity(CSVPrinter printer, List<CSVRecord> csvRecords) thro
         }
 
         String metricName = csvRecord.get(0);
-        // Metric FQN is just the name (no parent in current schema)
-        Metric metric;
-        try {
-          metric = Entity.getEntityByName(METRIC, metricName, "*", Include.NON_DELETED);
-        } catch (EntityNotFoundException ex) {
-          LOG.debug("Metric not found: {}, it will be created during import.", metricName);
+        // Metric FQN is just the name (no parent in current schema). Use a lightweight
+        // existence-check lookup; fields populated below from the CSV row are the source of truth.
+        Metric metric = findByNameOrNull(metricName, Include.NON_DELETED);
+        if (metric == null) {
           metric = new Metric().withName(metricName).withFullyQualifiedName(metricName);
         }
 

openmetadata-service/src/main/java/org/openmetadata/service/resources/metrics/MetricResource.java

@@ -65,6 +65,7 @@
 import org.openmetadata.service.resources.EntityResource;
 import org.openmetadata.service.security.Authorizer;
 import org.openmetadata.service.util.CSVExportResponse;
+import org.openmetadata.service.util.CSVImportResponse;
 
 @Path("/v1/metrics")
 @Tag(
@@ -727,7 +728,7 @@ public CsvImportResult importCsv(
             content =
                 @Content(
                     mediaType = "application/json",
-                    schema = @Schema(implementation = CsvImportResult.class)))
+                    schema = @Schema(implementation = CSVImportResponse.class)))
       })
   public Response importCsvAsync(
       @Context UriInfo uriInfo,