Merge pull request #20698 from wjywbs/lrb

Move alwayslink to lb_server_load_reporting_filter target.

BUILD

@@ -1392,6 +1392,7 @@ grpc_cc_library(
         "grpc++_base",
         "grpc_secure",
     ],
+    alwayslink = 1,
 )
 
 grpc_cc_library(
@@ -1438,7 +1439,6 @@ grpc_cc_library(
         "lb_server_load_reporting_filter",
         "lb_server_load_reporting_service_server_builder_plugin",
     ],
-    alwayslink = 1,
 )
 
 grpc_cc_library(