mas: Fix parsing on mas 3.0.0+. (#11179)

* mas: Fix parsing on mas 3.0.0+.

`mas` changed the formatting of `mas list` with version 3, which breaks
the parsing this module uses to determine which apps are installed.  In
particular, app IDs may now have leading space, which causes us to split
the string too early.

* Changelog fragment.

* Better format examples and changlog fragment.

changelogs/fragments/11179-mas-list-parsing.yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+  - mas - parse CLI output correctly when listing installed apps with mas 3.0.0+ (https://github.com/ansible-collections/community.general/pull/11179).

plugins/modules/mas.py

@@ -195,8 +195,14 @@ class Mas:
             rows = []
         apps = []
         for r in rows:
-            # Format: "123456789 App Name"
+            # mas 2.3.0 and older:
-            r = r.split(" ", 1)
+            # 123456789  App Name         (version)
+            # 4567890    App Name Longer  (version)
+            #
+            # mas 3.0.0 and newer:
+            # 123456789  App Name         (version)
+            #   4567890  App Name Longer  (version)
+            r = r.strip().split(" ", 1)
             if len(r) == 2:
                 apps.append(int(r[0]))