Default squash actions add pip (#41390)

* pip tests: remove trailing spaces

* pip tests: use Jinja tests

* fixup! pip tests: remove trailing spaces

* pip tests: use 'command' instead of 'shell' module

* pip tests: remove unused variable

* pip tests: use a package with fewer dependencies

sampleproject has one dependency: 'peppercorn' and peppercorn doesn't
have any dependency.

* pip tests: check that 'name' param handles list

* pip: squash package parameters

Note that squashing will be removed in 2.11, new code should directly
use a list with the 'name' parameter.

lib/ansible/config/base.yml

@@ -969,7 +969,7 @@ DEFAULT_SFTP_BATCH_MODE:
   yaml: {key: ssh_connection.sftp_batch_mode}
 DEFAULT_SQUASH_ACTIONS:
   name: Squashable actions
-  default: apk, apt, dnf, homebrew, openbsd_pkg, pacman, pkgng, yum, zypper
+  default: apk, apt, dnf, homebrew, openbsd_pkg, pacman, pip, pkgng, yum, zypper
   description:
     - Ansible can optimise actions that call modules that support list parameters when using ``with_`` looping.
       Instead of calling the module once for each item, the module is called once with the full list.