Revert "tast-tests: stabilize crostini fixtures"

This reverts commit bbe9e00691a647d10acbd7b54e1eddddbe5143ad.

Reason for revert: it caused multiple crostini fixture failures
b:234128639

Original change's description:
> tast-tests: stabilize crostini fixtures
>
> As part of crostini installation we continuously click turn on and next
> buttons until other buttons appear. For that, currently we use
> WaitUntilExists as a condition to stop clicking. This method polls for
> a condition until it is fulfilled. This works, if the first left click
> succeeded. However, if it did not, WaitUntilExists will poll until ctx
> is exhausted before returning. As the ctx duration it uses matches that
> of the left click, once it returns due to a timeout, we no longer have
> time left for yet another left click.
>
> Replace double-polling introduced by WaitUntilExists with a one off
> check to allow for repeated left clicks.
>
> BUG=b:231630463
> TEST=tast run dut crostini.AppGeditInstallUninstall.stable
>
> Change-Id: I123dfa17ae319afae74f456caaa1e9a8d45f0aea
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/tast-tests/+/3665328
> Commit-Queue: Alexey Shpakov <ashpakov@google.com>
> Reviewed-by: David Munro <davidmunro@google.com>
> Tested-by: Alexey Shpakov <ashpakov@google.com>
> Reviewed-by: Alvin Jia <alvinjia@google.com>

Bug: b:231630463
Change-Id: Ie91a4e97bb7a2c4102aa395db01ca5260b658ef7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/tast-tests/+/3672977
Commit-Queue: Alexey Shpakov <ashpakov@google.com>
Commit-Queue: Ben Reich <benreich@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Ben Reich <benreich@chromium.org>
Tested-by: Alexey Shpakov <ashpakov@google.com>
Auto-Submit: Alexey Shpakov <ashpakov@google.com>
diff --git a/src/chromiumos/tast/local/crostini/ui/settings/settings.go b/src/chromiumos/tast/local/crostini/ui/settings/settings.go
index 070a9ca..25538e7b0 100644
--- a/src/chromiumos/tast/local/crostini/ui/settings/settings.go
+++ b/src/chromiumos/tast/local/crostini/ui/settings/settings.go
@@ -210,8 +210,8 @@
 	defer func() { faillog.DumpUITreeAndScreenshot(cleanupCtx, tconn, "crostini_installer", retErr) }()
 	installButton := nodewith.Name("Install").Role(role.Button)
 	if err := uiauto.Combine("open Install and click button Next",
-		ui.LeftClickUntil(TurnOnButton, ui.Exists(nextButton)),
-		ui.LeftClickUntil(nextButton, ui.Exists(installButton)))(ctx); err != nil {
+		ui.LeftClickUntil(TurnOnButton, ui.WaitUntilExists(nextButton)),
+		ui.LeftClickUntil(nextButton, ui.WaitUntilExists(installButton)))(ctx); err != nil {
 		return errors.Wrap(err, "failed to click button Next on the installer")
 	}
 	return nil