Add ability to choose the operator when performing an entity lookup

Let's try to address feedback in the merge request and add a test coverage.

I put some test coverage for the new operator property, but it fails because of these lines:

// By default do a case-sensitive comparison.
    if (!$ignoreCase) {
      // Returns the entity's identifier.
      foreach ($results as $k => $identifier) {
        $entity = $this->entityTypeManager->getStorage($this->lookupEntityType)->load($identifier);
        $result_value = $entity instanceof ConfigEntityInterface ? $entity->get($this->lookupValueKey) : $entity->get($this->lookupValueKey)->value;
        if (($multiple && !in_array($result_value, $value, TRUE)) || (!$multiple && $result_value !== $value)) {
          unset($results[$k]);
        }
      }
    }

In the test example, $result_value is lucuma and $value is lucu.
That's why the result is removed.

Why do we have this? I haven't looked at the commit history yet. Perhaps the answer is there.

I published a few more commits - it's ready for review.

I self-reviewed it today and decided to go ahead and commit. If there are any suggestions/concerns, we can move them into a follow-up.

I'll also keep it open for backporting to 6.0 during the weekend so there is an opportunity to discuss if we can make it better.

Thanks!

I don't know what happened After #12, but all tests are failing now. Trying a patch to add missing return types.

Ops, wrong file

I reverted the last commit until we fix the test bot results.

Since I can't figure out why the test results are not showing up, but the tests are passing (we can see it in the job details), here is a new patch that contains MR changes + #16.

Here is a patch for 6.0.x version

Although the message is "Build Successful", the tests are passing according to the Test Report.

This is committed to 8.x-5.x and 6.0.x.
Thanks!