tests/formulae_dependents: another --ignore-dependencies fix

One more (and hopefully last) fix like #1305 and #1306. When we test
dependents of multiple formulae, a dependent of one formula being tested
can happen to be a dependency of another formula being tested. In this
case, we need the `--ignore-dependencies` option to force removal of the
dependent/dependency formula. When testing the dependents of the removed
formula, `brew install --only-dependencies` ensures that it is
reinstalled.

Fixes failure seen at https://github.com/Homebrew/homebrew-core/actions/runs/11923246241/job/33242018653?pr=198240.

lib/tests/formulae_dependents.rb

@@ -326,7 +326,7 @@ def install_dependent(dependent, testable_dependents, args:, build_from_source:
           test_step = steps.last
         end
 
-        test "brew", "uninstall", "--force", dependent.full_name
+        test "brew", "uninstall", "--force", "--ignore-dependencies", dependent.full_name
 
         all_tests_passed = (dependent_was_previously_installed || install_step.passed?) &&
                            linkage_step.passed? &&