Fixed errcheck issues in server/channels/api4/usage_test.go (#28644)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/channels/api4/usage_test.go

@@ -19,7 +19,8 @@ func TestGetPostsUsage(t *testing.T) {
 		th := Setup(t)
 		defer th.TearDown()
 
-		th.Client.Logout(context.Background())
+		_, err := th.Client.Logout(context.Background())
+		require.NoError(t, err)
 
 		usage, r, err := th.Client.GetPostsUsage(context.Background())
 		assert.Error(t, err)
@@ -57,7 +58,8 @@ func TestGetStorageUsage(t *testing.T) {
 		th := Setup(t)
 		defer th.TearDown()
 
-		th.Client.Logout(context.Background())
+		_, err := th.Client.Logout(context.Background())
+		require.NoError(t, err)
 
 		usage, r, err := th.Client.GetStorageUsage(context.Background())
 		assert.Error(t, err)
@@ -71,7 +73,8 @@ func TestGetTeamsUsage(t *testing.T) {
 		th := Setup(t)
 		defer th.TearDown()
 
-		th.Client.Logout(context.Background())
+		_, err := th.Client.Logout(context.Background())
+		require.NoError(t, err)
 
 		usage, r, err := th.Client.GetTeamsUsage(context.Background())
 		assert.Error(t, err)