MongoDB - Fix write_concern param (#18546)

* fix writeconcern defaulting to majority

* add changelog

* restart CI tests

* fix tests

* add package

changelog/18546.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+database/mongodb: Fix writeConcern set to be applied to any query made on the database
+```

plugins/database/mongodb/mongodb.go

@@ -210,9 +210,19 @@ func (m *MongoDB) DeleteUser(ctx context.Context, req dbplugin.DeleteUserRequest
 		db = "admin"
 	}
 
+	// Set the write concern. The default is majority.
+	writeConcern := writeconcern.New(writeconcern.WMajority())
+	opts, err := m.getWriteConcern()
+	if err != nil {
+		return dbplugin.DeleteUserResponse{}, err
+	}
+	if opts != nil {
+		writeConcern = opts.WriteConcern
+	}
+
 	dropUserCmd := &dropUserCommand{
 		Username:     req.Username,
-		WriteConcern: writeconcern.New(writeconcern.WMajority()),
+		WriteConcern: writeConcern,
 	}
 
 	err = m.runCommandWithRetry(ctx, db, dropUserCmd)