TrafficRoute test is flaky

[Icarus9913]

What happened?

This issue is used for tracing TrafficRoute e2e flaky tests:

wrong traffic split

https://github.com/kumahq/kuma/actions/runs/10943426810/job/30392838559

[FAILED] [19.664 seconds]
Traffic Route HTTP routing [It] should split traffic between internal and external destinations
github.com/kumahq/kuma/test/e2e_env/universal/trafficroute/traffic_route.go:677

Captured StdOut/StdErr Output

  [FAILED] Expected
      <map[string]int | len:2>: {"echo-v1": 64, "route-es-http": 36}
  to have {key: value} matching
      <map[interface {}]interface {} | len:1>: {
          <string>"echo-v1": <*matchers.BeNumericallyMatcher | 0x400101b080>{
              Comparator: "~",
              CompareTo: [<int>50, <int>10],
          },
      }
Error: It 09/19/24 18:16:56.687

curl exit status 22 by 40x

https://github.com/kumahq/kuma/actions/runs/10946133312/job/30392323827

[FAILED] [37.220 seconds]
Traffic Route [It] should route split traffic between the versions with 20/80 ratio
github.com/kumahq/kuma/test/e2e_env/universal/trafficroute/traffic_route.go:158

Captured StdOut/StdErr Output

  [FAILED] Timed out after 30.000s.
  The function passed to Eventually returned the following error:
      <*errors.errorString | 0xc000a024e0>: 
      stderr: '', exit status 22
      {
          s: "stderr: '', exit status 22",
      }
Error: It 09/19/24 18:30:27.61

https://github.com/kumahq/kuma/actions/runs/10943542451/job/30384877638

[FAILED] [34.363 seconds]
Traffic Route HTTP routing [It] should same splits with a different weights
github.com/kumahq/kuma/test/e2e_env/universal/trafficroute/traffic_route.go:420

Captured StdOut/StdErr Output

  [FAILED] Timed out after 30.001s.
  The function passed to Eventually returned the following error:
      <*errors.errorString | 0xc0006e0d20>: 
      stderr: '', exit status 22
      {
          s: "stderr: '', exit status 22",
      }
Error: It 09/19/24 17:19:24.789

[lahabana]

PR: #11496 likely removes this flakiness by always using a logical barrier to check the route is applied