fix: Spreadsheet - do not hide rows/columns for nonexistent freeze pane splits

[thevaadinman]

Description

Spreadsheet does not handle freeze panes correctly. In this case, SpreadsheetFactory.loadFreezePane(Spreadsheet) does not check if paneInformation.getVerticalSplitPosition() or paneInformation.getHorizontalSplitPosition() returns 0 before attempting to hide columns according to the saved scroll state.

By adding a check for a correct return value from paneInformation, this change fixes a situation where a document with a freeze pane that was scrolled before being saved would load incorrectly, resulting in the user being unable to scroll to the beginning of the document, and the rendering being corrupted.

Unfortunately, Spreadsheet does not provide a sane API for restoring the original scroll position, which is something that both MS Excel and LibreOffice Calc do. Adding this functionality is out-of-scope for this PR.

Fixes #8136.

Type of change

• Bugfix
• Feature

Checklist

• I have read the contribution guide: https://vaadin.com/docs/latest/contributing/overview
• I have added a description following the guideline.
• The issue is created in the corresponding repository and I have referenced it.
• I have added tests to ensure my change is effective and works as intended.
• New and existing tests are passing locally with my change.
• I have performed self-review and corrected misspellings.
• I have not completed some of the steps above and my pull request can be closed immediately.

Additional for Feature type of change

• Enhancement / new feature was discussed in a corresponding GitHub issue and Acceptance Criteria were created.

[sonarqubecloud]

Quality Gate passed

Issues
2 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