[pr test] increase T1-lag PR test timeout to 5 hours (sonic-net#11029)

Why I did it
Some PR test are timing out on T1-lag kvm test.

How I did it
Increase the timeout to 5 hours.

How to verify it
Test on this PR.

Signed-off-by: Ying Xie [email protected]

Author: yxieca

azure-pipelines.yml

@@ -184,7 +184,7 @@ stages:
   - job:
     pool: sonictest-t1-lag
     displayName: "kvmtest-t1-lag"
-    timeoutInMinutes: 240
+    timeoutInMinutes: 300
 
     steps:
     - template: .azure-pipelines/run-test-template.yml