🌱 fix sorting contributors before comparing in test

[spencerschrock]

What kind of change does this PR introduce?

test fix follow up of #4437

• PR title follows the guidelines defined in our pull request documentation

What is the current behavior?

The intention for the test was always to sort, but the wrong sort function was used. This led to an unsorted list, which was dependent on map iteration order, leading to flaky unit tests. This was reproducible with go test when passing a large --count option.

What is the new behavior (if this is a feature change)?**

The contributors are sorted correctly.

• Tests for the changes have been added (for bug fixes/features)

Which issue(s) this PR fixes

See https://github.com/ossf/scorecard/actions/runs/12300084637/job/34327383076#step:9:26

--- FAIL: Test_listContributors (0.00s)
    --- FAIL: Test_listContributors/multiple_contributors (0.00s)
        contributors_test.go:126: contributorsHandler.setup() mismatch (-want +got):
              []clients.User{
              	{
            - 		Login:            "[email protected]",
            + 		Login:            "[email protected]",
              		Companies:        {"testOrg"},
              		Organizations:    nil,
            - 		NumContributions: 1,
            + 		NumContributions: 2,
              		ID:               0,
              		IsBot:            false,
              	},
              	{
            - 		Login:            "[email protected]",
            + 		Login:            "[email protected]",
              		Companies:        {"testOrg"},
              		Organizations:    nil,
            - 		NumContributions: 2,
            + 		NumContributions: 1,
              		ID:               0,
              		IsBot:            false,
              	},
              }
FAIL

Special notes for your reviewer

Does this PR introduce a user-facing change?

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the release-note

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application as a result of this pull request.)

NONE

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.63%. Comparing base (353ed60) to head (54987c3).
Report is 82 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4455      +/-   ##
==========================================
+ Coverage   66.80%   68.63%   +1.82%     
==========================================
  Files         230      242      +12     
  Lines       16602    18032    +1430     
==========================================
+ Hits        11091    12376    +1285     
- Misses       4808     4848      +40     
- Partials      703      808     +105