e2e: fix some tests

[zirain]

1. prometheus address wrong on IPv6
2. make E2E_TIMEOUT configurable
3. skip EGUpgradeTest on IPv6

[codecov[bot]]

Codecov Report

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

Project coverage is 65.63%. Comparing base (97a5d68) to head (7899fdd). Report is 4 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #4729 +/- ## ========================================== + Coverage 65.58% 65.63% +0.04% ========================================== Files 211 211 Lines 31998 31998 ========================================== + Hits 20986 21002 +16 + Misses 9768 9758 -10 + Partials 1244 1238 -6 ```

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