Fix flaky functional test on account assignment

[smoy]

What changed?

• use the same target user and target ground for functional testing

Rationale

• the random failure depends on which user or group. so let's not fight randomness

How was it tested?

If it was manually verified, list the instructions for your reviewers to follow.

• [ ] Unit Tests
• [x] Functional Tests
• [ ] Manually Verified

[codecov[bot]]

Codecov Report

Patch coverage has no change and project coverage change: +9.81% :tada:

Comparison is base (e13b264) 73.23% compared to head (2e003f7) 83.04%. Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #612 +/- ## ========================================== + Coverage 73.23% 83.04% +9.81% ========================================== Files 105 105 Lines 12587 12587 ========================================== + Hits 9218 10453 +1235 + Misses 3369 2134 -1235 ``` | [Flag](https://app.codecov.io/gh/noqdev/iambic/pull/612/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=noqdev) | Coverage Δ | | |---|---|---| | [functional_tests](https://app.codecov.io/gh/noqdev/iambic/pull/612/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=noqdev) | `66.01% <ø> (?)` | | | [functional_tests_config_discovery](https://app.codecov.io/gh/noqdev/iambic/pull/612/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=noqdev) | `45.79% <ø> (?)` | | | [unit_tests](https://app.codecov.io/gh/noqdev/iambic/pull/612/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=noqdev) | `73.23% <ø> (ø)` | | 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=noqdev#carryforward-flags-in-the-pull-request-comment) to find out more. [see 51 files with indirect coverage changes](https://app.codecov.io/gh/noqdev/iambic/pull/612/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=noqdev)

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