fix(general): Support list definition in external custom policies

[inbalavital]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Problem
Loading external custom policies with a list-type definition block crashes with AttributeError: 'list' object has no attribute 'get' in get_complex_operator() in checkov/common/checks_infra/checks_parser.py:359

The validator at validate_check_config() checkov/common/checks_infra/checks_parser.py:193
explicitly accepts both list and dict definitions, but parse_raw_check() common/checks_infra/checks_parser.py:202 passed the list directly to _parse_raw_check() common/checks_infra/checks_parser.py:234, which assumes a dict.

Fix
In parse_raw_check() common/checks_infra/checks_parser.py:205, wrap list-type definitions as an implicit AND: [cond1, cond2] → {"and": [cond1, cond2]}. This is consistent with how the Bridgecrew platform represents compound policies.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my feature, policy, or fix is effective and works
• New and existing tests pass locally with my changes