Replace ast.literal_eval with json.loads for creator and publish attributes to avoid crashes on Unreal

[moonyuet]

Changelog Description

Ported from ynput/OpenPype#6318

Additional info

n/a

Testing notes:

1. Ayon -> Publish
2. Create Instance
3. Turn on/off Instance, or turn on/off setting
4. Save Instance
5. Should be worked as expected

[LiborBatek]

Each time I open Publisher containing some publish instance(s) it gives me error and no publish instances shown in the UI:

Traceback (most recent call last):
  File "C:\Work\REPO\ayon-core\client\ayon_core\pipeline\create\context.py", line 1020, in reset_instances
    creator.collect_instances()
  File "c:\Work\REPO\ayon-unreal\client\ayon_unreal\api\plugin.py", line 177, in collect_instances
    return self._default_collect_instances()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Work\REPO\ayon-unreal\client\ayon_unreal\api\plugin.py", line 83, in _default_collect_instances
    instance['publish_attributes'] = json.loads(
                                     ^^^^^^^^^^^
  File "c:\Program Files\Epic Games\UE_5.4\Engine\Binaries\ThirdParty\Python3\Win64\Lib\json\__init__.py", line 346, in loads
    return _default_decoder.decode(s)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Program Files\Epic Games\UE_5.4\Engine\Binaries\ThirdParty\Python3\Win64\Lib\json\decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Program Files\Epic Games\UE_5.4\Engine\Binaries\ThirdParty\Python3\Win64\Lib\json\decoder.py", line 353, in raw_decode
    obj, end = self.scan_once(s, idx)
               ^^^^^^^^^^^^^^^^^^^^^^
json.decoder.JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 2 (char 1)

[moonyuet]

@LiborBatek I tested again in my side, strangely it works for create_attributes but not publish_attributes. Probably we need to ask the contributor for more info to see why ast.literal_eval would crash their unreal.
@ccaillot can you test in the latest develop in Ayon to see if the issue still exists?