[webview_flutter] Fix XCUITest in Xcode 15 (#5071)

For some reason tapping the "Done" button in the XCUITest stopped working in Xcode 15, but tapping it via coordinates works, so switch to that as a workaround.

Fixes flutter/flutter#134971

packages/url_launcher/url_launcher_ios/example/ios/RunnerUITests/URLLauncherUITests.swift

@@ -31,7 +31,12 @@ class URLLauncherUITests: XCTestCase {
  XCTAssertTrue(app.buttons["ForwardButton"].waitForExistence(timeout: 30.0))
  XCTAssertTrue(app.buttons["Share"].exists)
  XCTAssertTrue(app.buttons["OpenInSafariButton"].exists)
- app.buttons["Done"].tap()
+ let doneButton = app.buttons["Done"]
+ XCTAssertTrue(doneButton.waitForExistence(timeout: 30.0))
+ // This should just be doneButton.tap, but for some reason that stopped working in Xcode 15;
+ // tapping via coordinate works, however.
+ doneButton.coordinate(withNormalizedOffset: CGVector()).withOffset(CGVector(dx: 10, dy: 10))
+ .tap()
  }
  }
 }