Add type hints to action and test plugins and to plugin utils; fix some bugs, and improve input validation (#11167)

* Add type hints to action and test plugins and to plugin utils. Also fix some bugs and add proper input validation.

* Combine lines.

Co-authored-by: Alexei Znamensky <103110+russoz@users.noreply.github.com>

* Extend changelog fragment.

* Move task_vars initialization up.

---------

Co-authored-by: Alexei Znamensky <103110+russoz@users.noreply.github.com>

plugins/plugin_utils/unsafe.py

@@ -5,8 +5,9 @@
 from __future__ import annotations
 
 import re
+import typing as t
 
-from collections.abc import Mapping, Set
+from collections.abc import Mapping, Sequence, Set
 from ansible.module_utils.common.collections import is_sequence
 from ansible.utils.unsafe_proxy import (
     AnsibleUnsafe,
@@ -17,14 +18,54 @@ _RE_TEMPLATE_CHARS = re.compile("[{}]")
 _RE_TEMPLATE_CHARS_BYTES = re.compile(b"[{}]")
 
 
-def make_unsafe(value):
+@t.overload
+def make_unsafe(value: None) -> None: ...
+
+
+@t.overload
+def make_unsafe(value: Mapping) -> dict: ...
+
+
+@t.overload
+def make_unsafe(value: Set) -> set: ...
+
+
+@t.overload
+def make_unsafe(value: tuple) -> tuple: ...
+
+
+@t.overload
+def make_unsafe(value: list) -> list: ...
+
+
+@t.overload
+def make_unsafe(value: Sequence) -> Sequence: ...
+
+
+@t.overload
+def make_unsafe(value: str) -> str: ...
+
+
+@t.overload
+def make_unsafe(value: bool) -> bool: ...
+
+
+@t.overload
+def make_unsafe(value: int) -> int: ...
+
+
+@t.overload
+def make_unsafe(value: float) -> float: ...
+
+
+def make_unsafe(value: t.Any) -> t.Any:
     if value is None or isinstance(value, AnsibleUnsafe):
         return value
 
     if isinstance(value, Mapping):
         return {make_unsafe(key): make_unsafe(val) for key, val in value.items()}
     elif isinstance(value, Set):
-        return set(make_unsafe(elt) for elt in value)
+        return {make_unsafe(elt) for elt in value}
     elif is_sequence(value):
         return type(value)(make_unsafe(elt) for elt in value)
     elif isinstance(value, bytes):