fix: improve includeWhen CEL expression validation

[aryasoni98]

This change modifies the validation logic to:

1. Use CEL type checking instead of evaluation
2. Skip validation of other expressions when includeWhen conditions indicate the resource won't be included
3. Fix array index access validation issues by properly respecting includeWhen conditions

Fixes #417

[a-hilaly]

Hi @aryasoni98, thanks for this PR. I'm closing this pr because:

the code has multiple compiler errors that would have been caught by local testing, also
caching and string checking CEL content doesn't solve the underlying issue in #417 it also appears that this code was LLM generated.

rven though this issue was assigned to you, please discuss your technical approach with the maintainers before writing code.