Add a setter for otel headers (#1809)

Add a setter for otel headers

Author: m-nagarajan

internal/venice-client-common/src/main/java/com/linkedin/venice/stats/VeniceMetricsConfig.java

@@ -302,6 +302,11 @@ public Builder setOtelAdditionalMetricsReader(MetricReader otelAdditionalMetrics
       return this;
     }
 
+    public Builder setOtelHeaders(Map<String, String> otelHeaders) {
+      this.otelHeaders = otelHeaders;
+      return this;
+    }
+
     /**
      * Extract and set otel configs
      */

internal/venice-client-common/src/test/java/com/linkedin/venice/stats/VeniceMetricsConfigTest.java

@@ -203,4 +203,14 @@ public void testSetOtelCustomDimensionsMapWithInvalidValue() {
         .extractAndSetOtelConfigs(otelConfigs)
         .build();
   }
+
+  @Test
+  public void testSetOtelHeaders() {
+    Map<String, String> otelHeaders = new HashMap<>();
+    otelHeaders.put("key1", "value1");
+
+    VeniceMetricsConfig config =
+        new Builder().setServiceName("TestService").setMetricPrefix("TestPrefix").setOtelHeaders(otelHeaders).build();
+    assertEquals(config.getOtelHeaders().get("key1"), "value1");
+  }
 }