refactor: change the hierarchy between test and testing

[AvivYossef-starkware]

Separate between test and testing. Now, the test depends on testing, meaning that cfg(test) also compiles the testing file,
but testing does not include a test file.

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This change is 

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.51%. Comparing base (5f0105f) to head (8727a04).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #211      +/-   ##
==========================================
- Coverage   63.74%   63.51%   -0.23%     
==========================================
  Files          36       36              
  Lines        1663     1669       +6     
  Branches     1663     1669       +6     
==========================================
  Hits         1060     1060              
- Misses        552      558       +6     
  Partials       51       51              

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[AvivYossef-starkware]

Reviewable status: 0 of 7 files reviewed, 1 unresolved discussion (waiting on @dorimedini-starkware)

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crates/committer/Cargo.toml line 27 at r1 (raw file):

hex.workspace = true
rand.workspace = true
rstest.workspace = true

its removed since its only dev-dependencies but we couldn't remove it until today since testing and test was mixed

[dorimedini-starkware]

Reviewed 7 of 7 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @AvivYossef-starkware)

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crates/committer/src/patricia_merkle_tree.rs line 12 at r1 (raw file):

#[cfg(feature = "testing")]
pub mod testing_utils;

Suggestion:

#[cfg(test)]
pub mod internal_test_utils;

#[cfg(feature = "testing")]
pub mod external_test_utils;

[dorimedini-starkware]

Reviewed 7 of 7 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @AvivYossef-starkware)

[dorimedini-starkware]

Reviewed 5 of 5 files at r3, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @AvivYossef-starkware)