gem: fix soundness issue when uninstalling default gems on Ubuntu (#10689)

* Attempt to fix gem soundness issue

* Return command execution

* Fix value error

* Attempt to fix failling tests

* Fix minor issues

* Update changelog

* Update tests/integration/targets/gem/tasks/main.yml

Co-authored-by: Alexei Znamensky <103110+russoz@users.noreply.github.com>

* Update changelogs/fragments/10689-gem-prevent-soundness-issue.yml

Co-authored-by: Alexei Znamensky <103110+russoz@users.noreply.github.com>

* Remove state and name from gem error message

* Improve gem uninstall check

* Make unit tests pass

* Fix linting issues

* gem: Remove length chenck and adapt unit tests

* Adapt gem unit tests

* gem: improve error msg

* Fix sanity error

* Fix linting issue

---------

Co-authored-by: Alexei Znamensky <103110+russoz@users.noreply.github.com>

tests/integration/targets/gem/tasks/main.yml

@@ -212,3 +212,18 @@
         that:
           - install_gem_result is changed
           - not gem_bindir_stat.stat.exists
+
+    - name: Attempt to uninstall default gem 'json'
+      community.general.gem:
+        name: json
+        state: absent
+      when: ansible_distribution == "Ubuntu"
+      register: gem_result
+      ignore_errors: true
+
+    - name: Assert gem uninstall failed as expected
+      when: ansible_distribution == "Ubuntu"
+      assert:
+        that:
+          - gem_result is failed
+          - gem_result.msg.startswith("Failed to uninstall gem 'json'")