e2e: use appropriate values for upgrade test

.github/workflows/build_and_test.yaml

@@ -136,24 +136,19 @@ jobs:
         - version: v1.30.10
           ipFamily: ipv4
           profile: default
-          loadQPS: 1000
         - version: v1.31.6
           ipFamily: ipv4
           profile: default
-          loadQPS: 2000
         - version: v1.32.3
           ipFamily: ipv6  # only run ipv6 test on this version to save time
           profile: default
-          loadQPS: 3000
         # TODO: this's IPv4 first, need a way to test IPv6 first.
         - version: v1.33.0
           ipFamily: dual  # only run dual test on latest version to save time
           profile: default
-          loadQPS: 4000
         - version: v1.33.0
           ipFamily: dual  # only run dual test on latest version to save time
           profile: gateway-namespace-mode
-          loadQPS: 5000
     steps:
     - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683  # v4.2.2
     - uses: ./tools/github-actions/setup-deps
@@ -177,10 +172,11 @@ jobs:
         IP_FAMILY: ${{ matrix.target.ipFamily }}
         KUBE_DEPLOY_PROFILE: ${{ matrix.target.profile }}
         E2E_TIMEOUT: 1h
-        # use the loadQPS from the matrix to set the QPS for the E2E tests
-        # this is used to determine whether the flaky tests are due to load or not
-        E2E_BACKEND_UPGRADE_QPS: ${{ matrix.target.loadQPS }}
         NUM_WORKERS: 2
+        # QPS more than 3000 may cause e2e flaky test.
+        # This is not the limit of Envoy Gateway,
+        # but the limit of running e2e tests in github CI.
+        E2E_BACKEND_UPGRADE_QPS: "3000"
       run: make e2e
 
   benchmark-test: