Improve stability of Docker integration tests. (#46005)

test/integration/targets/docker_stack/tasks/test_stack.yml

@@ -1,3 +1,8 @@
+- name: Make sure we're not already using Docker swarm
+  docker_swarm:
+    state: absent
+    force: true
+
 - name: Create a Swarm cluster
   docker_swarm:
     state: present

test/integration/targets/docker_swarm/tasks/test_swarm.yml

@@ -1,3 +1,8 @@
+- name: Make sure we're not already using Docker swarm
+  docker_swarm:
+    state: absent
+    force: true
+
 - name: Test parameters with state=present
   docker_swarm:
     state: present