fix Windows env handling (#22927)

* fixes #22441
* fixes #22655
* moves all env handling into the exec wrapper; this should work for everything but raw, which is consistent with non-Windows.

test/integration/targets/win_script/files/test_script_with_env.ps1

@@ -0,0 +1 @@
+$env:taskenv

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

@@ -192,3 +192,16 @@
     that:
       - "test_script_bool_result.stdout_lines[0] == 'System.Boolean'"
       - "test_script_bool_result.stdout_lines[1] == 'True'"
+
+- name: run test script that uses envvars
+  script: test_script_with_env.ps1
+  environment:
+    taskenv: task
+  register: test_script_env_result
+
+- name: ensure that script ran and that environment var was passed
+  assert:
+    that:
+    - test_script_env_result | succeeded
+    - test_script_env_result.stdout_lines[0] == 'task'
+