[stable-2.12] Update setup_pexpect to prefer pip user installs.

This works around issues on RHEL 7.9 when an old version of pexpect is installed from an OS package.
(cherry picked from commit 27fe26edbf)

Co-authored-by: Matt Clay <matt@mystile.com>

ci_complete

test/integration/targets/setup_pexpect/tasks/main.yml

@@ -3,8 +3,17 @@
     src: constraints.txt
     dest: "{{ remote_tmp_dir }}/pexpect-constraints.txt"
 
+- name: Install pexpect with --user
+  pip:
+    name: pexpect
+    extra_args: '--user --constraint "{{ remote_tmp_dir }}/pexpect-constraints.txt"'
+    state: present
+  ignore_errors: yes  # fails when inside a virtual environment
+  register: pip_user
+
 - name: Install pexpect
   pip:
     name: pexpect
     extra_args: '--constraint "{{ remote_tmp_dir }}/pexpect-constraints.txt"'
     state: present
+  when: pip_user is failed