[Rust] Validate null counts when building arrays

[asfimport]

ArrayDataBuilder allows the user to specify a null count, alternatively calculating it if it is not set.

The problem is that the user-specified null count is never validated against the actual count of the buffer.

I suggest removing the ability to specify a null-count, and instead always calculating it.

Reporter: Neville Dipale / @nevi-me
Assignee: Neville Dipale / @nevi-me

PRs and other links:

• GitHub Pull Request #9041

_{Note: This issue was originally created as ARROW-11063. Please see the migration documentation for further details.}

[asfimport]

Andrew Lamb / @alamb:
Issue resolved by pull request 9041
#9041