feat: Chunk array method in models

[patel-vansh]

Description
This PR adds a chunkArray() method in CodeIgniter\Model class which allows users to get chunk as a whole instead of single rows, so that they can easily use functions like array_column(...) inside the closure.

Related to this forum thread.

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[patel-vansh]

I guess this PR can only be merged after merging the devlop branch in 4.8, for that time trait linting.

[michalsn]

You can rebase, although I would wait for changes from #9961.

Two things:

1. I would change the name to chunkRows() since “array” in the name may be misleading, even though it technically describes the type passed to the callback.
2. Since both methods that handle chunk results are nearly identical, I would abstract the shared logic, maybe like this:

private function iterateChunks(int $size): Generator
{
    if ($size <= 0) {
        throw new InvalidArgumentException('$size must be a positive integer.');
    }

    $total  = $this->builder()->countAllResults(false);
    $offset = 0;

    while ($offset < $total) {
        $builder = clone $this->builder();
        $rows    = $builder->get($size, $offset);

        if (! $rows) {
            throw DataException::forEmptyDataset('chunk');
        }

        $rows = $rows->getResult($this->tempReturnType);
        $offset += $size;

        if ($rows === []) {
            continue;
        }

        yield $rows;
    }
}

public function chunk(int $size, Closure $userFunc)
{
    foreach ($this->iterateChunks($size) as $rows) {
        foreach ($rows as $row) {
            if ($userFunc($row) === false) {
                return;
            }
        }
    }
}

public function chunkRows(int $size, Closure $userFunc)
{
    foreach ($this->iterateChunks($size) as $rows) {
        if ($userFunc($rows) === false) {
            return;
        }
    }
}

[patel-vansh]

I guess you're right. I will wait for #9961 to merge and then create a common method for both. Thanks for review @michalsn. :)