add e2e for WorkloadRebalancer

[chaosi-zju]

What type of PR is this?

/kind failing-test

What this PR does / why we need it:

add e2e for WorkloadRebalancer

Which issue(s) this PR fixes:

Fixes part of #4840

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 53.07%. Comparing base (6e5a602) to head (64593ac). Report is 18 commits behind head on master.

:exclamation: Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #4869 +/- ## ========================================== + Coverage 52.98% 53.07% +0.08% ========================================== Files 250 251 +1 Lines 20421 20387 -34 ========================================== Hits 10820 10820 + Misses 8881 8854 -27 + Partials 720 713 -7 ``` | [Flag](https://app.codecov.io/gh/karmada-io/karmada/pull/4869/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=karmada-io) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/karmada-io/karmada/pull/4869/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=karmada-io) | `53.07% <ø> (+0.08%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=karmada-io#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[karmada-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: To complete the pull request process, please assign xishanyongye-chang after the PR has been reviewed. You can assign the PR to them by writing /assign @xishanyongye-chang in a comment when ready.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files: - **[pkg/controllers/OWNERS](https://github.com/karmada-io/karmada/blob/master/pkg/controllers/OWNERS)** - **[test/OWNERS](https://github.com/karmada-io/karmada/blob/master/test/OWNERS)** Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[chaosi-zju]

/hold

for #4875