home interface plug attribute "read: all" triggers ValidationError

[florcabral]

Bug Description

Snapcraft fails to compile a snap when trying to use the home interface plug attribute "read: all".
This ValidationError is thrown: Input should be a valid list [type=list_type, input_value={'home': {'read': ['all']}}, input_type=dict].
The "read: all" feature seems to be introduced by this MR, and is documented in the home interfaces doc. Its description is "read (plug): optional, when set to ‘all’, also allows reading non-hidden files in the home directories of all users as traditional file permissions allow."

If the plug is defined separately, a warning is issued: INFO snap "os-release" has bad plugs or slots: home-all (home plug requires "read" be 'all'), but no access to home is given. Ie,

plugs:
  home-all:
    interface: home
    read: [all]

To Reproduce

Try to build a snap (ie, simple example provided below, taken from snapcraft docs) using the home interface's read attribute:

    plugs: 
      home:
        read: all

Environment

Ubuntu 24.04, LXD

snapcraft.yaml

name: os-release
base: core22
version: '0.2'
summary: Outputs the contents of /etc/os-release
description: Prints the contents of os-release
grade: stable
confinement: strict
apps:
  part-os-release:
    command: bin/os-release.sh
    plugs: 
      home:
        read: [all]
parts:
  part-os-release:
    plugin: dump
    source: .
    organize:
      os-release.sh: bin/

Relevant log output

$ snapcraft 
Traceback (most recent call last):
  File "/snap/snapcraft/13008/bin/snapcraft", line 8, in <module>
    sys.exit(main())
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/snapcraft/application.py", line 485, in main
    return cli.run()
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/snapcraft/cli.py", line 252, in run
    _run_dispatcher(dispatcher, global_args)
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/snapcraft/cli.py", line 225, in _run_dispatcher
    dispatcher.run()
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/craft_cli/dispatcher.py", line 494, in run
    return self._loaded_command.run(self._parsed_command_args)
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/snapcraft/commands/core22/lifecycle.py", line 266, in run
    super().run(parsed_args)
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/snapcraft/commands/core22/lifecycle.py", line 139, in run
    parts_lifecycle.run(self.name, parsed_args)
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/snapcraft/parts/lifecycle.py", line 102, in run
    project = models.Project.unmarshal(yaml_data_for_arch)
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/craft_application/models/base.py", line 61, in unmarshal
    return cls.model_validate(data)
  File "/snap/snapcraft/13008/lib/python3.10/site-packages/pydantic/main.py", line 596, in model_validate
    return cls.__pydantic_validator__.validate_python(
pydantic_core._pydantic_core.ValidationError: 1 validation error for Project
apps.part-os-release.plugs
  Input should be a valid list [type=list_type, input_value={'home': {'read': ['all']}}, input_type=dict]
    For further information visit https://errors.pydantic.dev/2.9/v/list_type

Additional context

No response