Concurrency issue with use find client

[PedroMarianoAlmeida]

Possible fix for #418

I created a new test that failed for the current useFind and passed for the new one

I basically removed the useRef and move the Initial Fetch into the Effect, this broke the Verify reference stability between rerenders test so I needed to update the refresh action on useFindReducer to compare the values properly (I feel that there is room from improvement on this part).

[CLAassistant]

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[PedroMarianoAlmeida]

Test coverage:

My new test (Immediate update before effect registration (race condition test) with current useFind

Test code:

  Tinytest.addAsync(
    'useFind - Immediate update before effect registration (race condition test)',
    async function (test, completed) {
      const container = document.createElement('div');
      document.body.appendChild(container);

      const TestDocs = new Mongo.Collection(null);
      // Insert a single document.
      TestDocs.insert({ id: 1, val: 'initial' });

      const Test = () => {
        const docs = useFind(() => TestDocs.find(), []);
        return (
          <div data-testid="doc-value">
            {docs && docs[0] && docs[0].val}
          </div>
        );
      };

      // Render the component.
      ReactDOM.render(<Test />, container);

      // Immediately update the document (this should occur
      // after the synchronous fetch in the old code but before the effect attaches).
      TestDocs.update({ id: 1 }, { $set: { val: 'updated' } });

      // Wait until the rendered output reflects the update.
      await waitFor(() => {
        const node = container.querySelector('[data-testid="doc-value"]');
        if (!node || !node.textContent.includes('updated')) {
          throw new Error('Updated value not rendered yet');
        }
      }, { container, timeout: 500 });

      test.ok(
        container.innerHTML.includes('updated'),
        'Document should display updated value; the old code would fail to capture this update.'
      );

      document.body.removeChild(container);
      completed();
    }
  );

[nachocodoner]

@PedroMarianoAlmeida: Sorry, 🙏. When I merged and deleted tests-3.x branch your PR based on that branch closed automatically.

Could you reopen the PR with the same contents and ensure to get latest master on it? We have also included CI checks #424

[PedroMarianoAlmeida]

Sure! I will!