fix: curp wal

[bsbds]

Depends-On: #687

Some fixes and improvements for the WAL storage

Please briefly answer these questions:

• what problem are you trying to solve? (or if there's no problem, what's the motivation for this change?)

• what changes does this pull request make?

• are there any non-obvious implications of these changes? (does it break compatibility with previous versions, etc)

[mergify[bot]]

@bsbds Convert your pr to draft since CI failed

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 83.37408% with 68 lines in your changes missing coverage. Please review.

Project coverage is 75.71%. Comparing base (e35b35a) to head (591c0ee). Report is 132 commits behind head on master.

Files	Patch %	Lines
crates/curp/src/server/storage/wal/mod.rs	73.41%	20 Missing and 22 partials :warning:
crates/curp/src/server/storage/wal/test_util.rs	71.42%	16 Missing :warning:
crates/curp/src/server/storage/wal/error.rs	0.00%	6 Missing :warning:
crates/curp/src/server/storage/wal/tests.rs	97.39%	3 Missing :warning:
crates/curp/src/server/storage/wal/config.rs	92.30%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #854 +/- ## ========================================== + Coverage 75.55% 75.71% +0.15% ========================================== Files 180 192 +12 Lines 26938 28128 +1190 Branches 26938 28128 +1190 ========================================== + Hits 20353 21296 +943 - Misses 5366 5514 +148 - Partials 1219 1318 +99 ```

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[CrystalAnalyst]

LGTM