feat: Add `as_completed_safe()`

[codecov[bot]]

Codecov Report

Patch coverage: 95.65% and project coverage change: -4.19 :warning:

Comparison is base (bd3e26a) 78.49% compared to head (dce64ce) 74.31%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #52 +/- ## ========================================== - Coverage 78.49% 74.31% -4.19% ========================================== Files 16 17 +1 Lines 1330 1347 +17 ========================================== - Hits 1044 1001 -43 - Misses 286 346 +60 ``` | [Impacted Files](https://codecov.io/gh/achimnol/aiotools/pull/52?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joongi+Kim) | Coverage Δ | | |---|---|---| | [src/aiotools/taskgroup/persistent\_compat.py](https://codecov.io/gh/achimnol/aiotools/pull/52?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joongi+Kim#diff-c3JjL2Fpb3Rvb2xzL3Rhc2tncm91cC9wZXJzaXN0ZW50X2NvbXBhdC5weQ==) | `82.81% <50.00%> (-0.53%)` | :arrow_down: | | [src/aiotools/taskgroup/\_\_init\_\_.py](https://codecov.io/gh/achimnol/aiotools/pull/52?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joongi+Kim#diff-c3JjL2Fpb3Rvb2xzL3Rhc2tncm91cC9fX2luaXRfXy5weQ==) | `100.00% <100.00%> (ø)` | | | [src/aiotools/taskgroup/persistent.py](https://codecov.io/gh/achimnol/aiotools/pull/52?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joongi+Kim#diff-c3JjL2Fpb3Rvb2xzL3Rhc2tncm91cC9wZXJzaXN0ZW50LnB5) | `87.36% <100.00%> (+4.94%)` | :arrow_up: | | [src/aiotools/taskgroup/utils.py](https://codecov.io/gh/achimnol/aiotools/pull/52?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joongi+Kim#diff-c3JjL2Fpb3Rvb2xzL3Rhc2tncm91cC91dGlscy5weQ==) | `100.00% <100.00%> (ø)` | | ... and [4 files with indirect coverage changes](https://codecov.io/gh/achimnol/aiotools/pull/52/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joongi+Kim) Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joongi+Kim). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joongi+Kim)

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