[UI Tests] Fix incorrect Settings Page launch method in UI test framework (#40367)

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fix/what does it change/how was it tested (even manually, if necessary)?
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## Summary of the Pull Request
### Root Cause
The UI test framework previously attempted to launch
PowerToys.Settings.exe directly.
However, this bypasses the PowerToys Runner, which is required for
proper interaction
and communication between runner.

### Fix
1. This change updates the launch mechanism to start PowerToys through
the Runner
with the appropriate argument ("--open-settings").
2. Prevents the Debug dialog from appearing in test runs

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## PR Checklist

- [ ] **Closes:** #xxx
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

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or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

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## Validation Steps Performed

src/common/UITestAutomation/UITestBase.cs

@@ -68,16 +68,6 @@ namespace Microsoft.PowerToys.UITest
 
             this.sessionHelper = new SessionHelper(scope).Init();
             this.Session = new Session(this.sessionHelper.GetRoot(), this.sessionHelper.GetDriver(), scope, size);
-
-            if (this.scope == PowerToysModule.PowerToysSettings)
-            {
-                // close Debug warning dialog if any
-                // Such debug warning dialog seems only appear in PowerToys Settings
-                if (this.FindAll("DEBUG").Count > 0)
-                {
-                    this.Find("DEBUG").Find<Button>("Close").Click();
-                }
-            }
         }
 
         /// <summary>