Move uses of to_bytes, to_text, to_native to use the module_utils version (#17423)

We couldn't copy to_unicode, to_bytes, to_str into module_utils because
of licensing.  So once created it we had two sets of functions that did
the same things but had different implementations.  To remedy that, this
change removes the ansible.utils.unicode versions of those functions.

lib/ansible/plugins/callback/__init__.py

@@ -24,12 +24,10 @@ import difflib
 import warnings
 from copy import deepcopy
 
-from ansible.compat.six import string_types
-
 from ansible import constants as C
-from ansible.vars import strip_internal_keys
+from ansible.module_utils._text import to_text
 from ansible.utils.color import stringc
-from ansible.utils.unicode import to_unicode
+from ansible.vars import strip_internal_keys
 
 try:
     from __main__ import display as global_display
@@ -37,14 +35,15 @@ except ImportError:
     from ansible.utils.display import Display
     global_display = Display()
 
-__all__ = ["CallbackBase"]
-
 try:
     from __main__ import cli
 except ImportError:
-    # using API w/o cli 
+    # using API w/o cli
     cli = False
 
+__all__ = ["CallbackBase"]
+
+
 class CallbackBase:
 
     '''
@@ -146,8 +145,8 @@ class CallbackBase:
                             after_header = "after: %s" % diff['after_header']
                         else:
                             after_header = 'after'
-                        differ = difflib.unified_diff(to_unicode(diff['before']).splitlines(True),
-                                                      to_unicode(diff['after']).splitlines(True),
+                        differ = difflib.unified_diff(to_text(diff['before']).splitlines(True),
+                                                      to_text(diff['after']).splitlines(True),
                                                       fromfile=before_header,
                                                       tofile=after_header,
                                                       fromfiledate='',
@@ -166,7 +165,7 @@ class CallbackBase:
                         if has_diff:
                             ret.append('\n')
                     if 'prepared' in diff:
-                        ret.append(to_unicode(diff['prepared']))
+                        ret.append(to_text(diff['prepared']))
             except UnicodeDecodeError:
                 ret.append(">> the files are different, but the diff library cannot compare unicode strings\n\n")
         return u''.join(ret)
@@ -362,4 +361,3 @@ class CallbackBase:
 
     def v2_runner_retry(self, result):
         pass
-