Use WRED red for DNX (#15126)

Description of PR
Braodcom DNX only supports WRED red. So update test accordingly.

snappi_tests/ecn/test_dequeue_ecn_with_snappi.py::test_dequeue_ecn
-------------------------------- live log call ---------------------------------
05:51:48 snappi_api.warning L1138 WARNING| Capture was not stopped for this port Port 0
FAILED [100%]

syntax error is fixed. Okay to merge. The new failure E       Failed: Only capture 0/101 IP packets. is a different issue. that can be handled in another PR.

co-authorized by: jianquanye@microsoft.com

tests/common/snappi_tests/common_helpers.py

@@ -472,20 +472,20 @@ def config_wred(host_ans, kmin, kmax, pmax, profile=None, asic_value=None):
 
     color = 'green'
 
-    # Broadcom ASIC only supports RED.
-    if asic_type == 'broadcom':
+    # Broadcom DNX ASIC only supports RED.
+    if "platform_asic" in host_ans.facts and host_ans.facts["platform_asic"] == "broadcom-dnx":
         color = 'red'
 
-    kmax_arg = '-{}max' % color[0]
-    kmin_arg = '-{}min' % color[0]
+    kmax_arg = '-{}max'.format(color[0])
+    kmin_arg = '-{}min'.format(color[0])
 
     for p in profiles:
         """ This is not the profile to configure """
         if profile is not None and profile != p:
             continue
 
-        kmin_old = int(profiles[p]['{}_min_threshold' % color])
-        kmax_old = int(profiles[p]['{}_max_threshold' % color])
+        kmin_old = int(profiles[p]['{}_min_threshold'.format(color)])
+        kmax_old = int(profiles[p]['{}_max_threshold'.format(color)])
 
         if kmin_old > kmax_old:
             return False