fix(web-app-preview): optionally access route query

[LukasHirt]

Description

When filtering out files in preview app, access route query optionally in case it is undefined to prevent broken loading.

Related Issue

• Fixes Preview feature makes the app unresponsive #12108
• resolves PNG file fails to load after editing linked share password in web 11.1.1, causing infinite loading loop #12106

Motivation and Context

The app loads even when the route query got somehow lost.

How Has This Been Tested?

• test environment: chrome & 🤖
• test case 1: added unit test
• test case 2: open the editor without the route query

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests
• Documentation
• Maintenance (e.g. dependency updates or tooling)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[anon-pradip]

Thanks. Checked and fixes the issue: #12106

[saw-jan]

Also fixes #12108
Click on Preview action doesn't do anything. so it's good for this PR.