Update _index.md | make it clearer that facets value include restrict…

…ed tests (#27399)

* Update _index.md | make it clearer that facets value might come from restricted tests

* Apply suggestions from code review

Co-authored-by: Alicia Scott <aliciascott@users.noreply.github.com>

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Co-authored-by: Alicia Scott <aliciascott@users.noreply.github.com>

content/en/synthetics/explore/_index.md

@@ -67,6 +67,9 @@ The default facets include the following:
 | `Notification` | The handle used by the Synthetic test for notifications.                      |
 | `Env`          | The environment the Synthetic test is running on.                             |
 | `CI/CD Execution Rule` | The status of the test run: `Blocking`, `Non-blocking`, or `Skipped`. |
+| `Endpoint`     | The url or domain the test is targeting.                                      |
+
+<div class="alert alert-info"> Note: You might see facet values originating from tests you don't have access to. </div>
 
 The **Tags** panel below **Synthetic Filters** lists several default tags you can use to identify your tests.