add back test_bgp_stress_link_flap into PR test (#14709)

.azure-pipelines/pr_test_scripts.yaml

@@ -19,6 +19,7 @@ t0:
   - bgp/test_bgp_speaker.py
   - bgp/test_bgp_update_timer.py
   - bgp/test_bgpmon.py
+  - bgp/test_bgp_stress_link_flap.py
   - bgp/test_bgp_session.py
   - cacl/test_cacl_application.py
   - cacl/test_cacl_function.py
@@ -266,6 +267,7 @@ t1-lag:
   - bgp/test_bgp_multipath_relax.py
   - bgp/test_bgp_update_timer.py
   - bgp/test_bgpmon.py
+  - bgp/test_bgp_stress_link_flap.py
   - bgp/test_bgp_session.py
   - bgp/test_traffic_shift.py
   - configlet/test_add_rack.py
@@ -449,7 +451,6 @@ dpu:
   - dash/test_dash_vnet.py
 
 onboarding_t0:
-  - bgp/test_bgp_stress_link_flap.py
   # We will add a batch of T0 control plane cases and fix the failed cases later
   - pfcwd/test_pfcwd_all_port_storm.py
   - pfcwd/test_pfcwd_function.py
@@ -461,7 +462,6 @@ onboarding_t0:
 
 
 onboarding_t1:
-  - bgp/test_bgp_stress_link_flap.py
   - snmp/test_snmp_link_local.py
   - lldp/test_lldp_syncd.py