Replacing require.nil in api layer (#16906)

* Replacing require.nil in api layer

* Fixing some tests

* Fixing tests

* Addressing PR review comments

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

api4/brand_test.go

@@ -34,7 +34,7 @@ func TestUploadBrandImage(t *testing.T) {
 	Client := th.Client
 
 	data, err := testutils.ReadTestFile("test.png")
-	require.Nil(t, err)
+	require.NoError(t, err)
 
 	_, resp := Client.UploadBrandImage(data)
 	CheckForbiddenStatus(t, resp)
@@ -60,7 +60,7 @@ func TestDeleteBrandImage(t *testing.T) {
 	defer th.TearDown()
 
 	data, err := testutils.ReadTestFile("test.png")
-	require.Nil(t, err)
+	require.NoError(t, err)
 
 	_, resp := th.SystemAdminClient.UploadBrandImage(data)
 	CheckCreatedStatus(t, resp)