Reduce m365 worker thread count from 7 to 2 (#6103)

This commit reduces the m365 worker thread count from 7 to 2.
This is because the worker thread is per host and we need to ensure
there are not too many threads in total to avoid api throttling.

The suggestion is to estimate based on 2 ~ 4 OCU. Original 7 is the
estimated based on total threads. Changing to 2 would fit for 4 OCU.

Signed-off-by: Wenjie Yao <[email protected]>
Co-authored-by: Wenjie Yao <[email protected]>

Author: wjyao0316

data-prepper-plugins/saas-source-plugins/microsoft-office365-source/src/main/java/org/opensearch/dataprepper/plugins/source/microsoft_office365/Office365SourceConfig.java

@@ -21,7 +21,7 @@
  */
 @Getter
 public class Office365SourceConfig implements CrawlerSourceConfig {
-    private static final int NUMBER_OF_WORKERS = 7;
+    private static final int NUMBER_OF_WORKERS = 2;
 
     /**
      * The Office 365 tenant ID that uniquely identifies the Microsoft Entra organization.

data-prepper-plugins/saas-source-plugins/microsoft-office365-source/src/test/java/org/opensearch/dataprepper/plugins/source/microsoft_office365/Office365SourceConfigTest.java

@@ -57,6 +57,6 @@ void testDefaultValues() throws Exception {
         Office365SourceConfig config = createConfig();
 
         assertFalse(config.isAcknowledgments());
-        assertEquals(7, config.getNumberOfWorkers());
+        assertEquals(2, config.getNumberOfWorkers());
     }
 }