Bugfix touch interaction - adds correct reset value to startPosition

[til2000]

Cross-references to related issues.
Associated issues: #3137

Notes re. the content of the pull request.

This PR fixes an issue which occurs when using touch devices.

• The originally occurring error originated in an array access (ie if( r.touchData.startPosition[0] == earlier[0] ..., if(... && startPosition[i] && ...) while startPosition was set to null instead of its initial value [null, null, null, null, ...]
• The correct initial value for startPosition is defined in this codeline

Checklist

Author:

• The proper base branch has been selected. New features go on unstable. Bug-fix patches can go on either unstable or master.
• N/A -- Automated tests have been included in this pull request, if possible, for the new feature(s) or bug fix. Check this box if tests are not pragmatically possible (e.g. rendering features could include screenshots or videos instead of automated tests).
• The associated GitHub issues are included (above).
• Notes have been included (above).

Reviewers:

• All automated checks are passing (green check next to latest commit).
• At least one reviewer has signed off on the pull request.
• For bug fixes: Just after this pull request is merged, it should be applied to both the master branch and the unstable branch. Normally, this just requires cherry-picking the corresponding merge commit from master to unstable -- or vice versa.

[maxkfranz]

@til2000, thank you for the pull request. I'll try to set aside some time so that we can this merged and released soon.

[maxkfranz]

This isn't easily reproducible, but the mitigation seems as though it wouldn't cause any harm. Merged.