[release/10.0] Fix and un-quarantine CanUseAntiforgeryAfterInitialRender test

[github-actions]

Backport of #63640 to release/10.0

/cc @oroztocil

Fix and un-quarantine CanUseAntiforgeryAfterInitialRender test

Fix and un-quarantine a flaky E2E test for Blazor.

Description

The ServerRenderingTests.FormHandlingTests.CanUseAntiforgeryAfterInitialRender test was flaky due to a race condition between re-rendering an element and checking its text value in the test assertion.

As the final step of the test, we check the text value of a specific DOM element. There was a race condition due to which the element can get re-rerendered between the moment when we acquire a WebElement reference to the DOM element (using the Browser.Exists method) and when we read the element's text value. When that happens, StaleElementReferenceException is thrown.

The PR tries to remove the flakiness by:

• Making the tested DOM element rendered only during interactive rendering and not during static rendering.
• Wrapping the two-step operation of retrieving the element reference and reading its text value inside a retry block (provided by the Selenium waiting API).

Fixes #63640

Customer Impact

The change increases the test coverage of our code.

Regression?

• Yes
• No

Risk

• High
• Medium
• Low

Does not impact shipped code.

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

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When servicing release/2.3

• Make necessary changes in eng/PatchConfig.props