`validated` and `is_fully_validated` flags doesn't need to be part of PartialEq

[alamb]

It seems like the validated and is_fully_validated flags doesn't need to be part of a logical type check? Like two variants can be equal by value even if one is fully validated and one is not

I would expect the following to pass for all variants and metadata

let variant1 = Variant::new(metadata, buffers);
let variant2 = Variant::new(metadata, buffers).with_full_validation();
assert_eq!(variant1, variant2)

Originally posted by @alamb in #7943 (comment)

[abacef]

take

[alamb]

label_issue.py automatically added labels {'parquet'} from #7961