fix(measurements): handle multiple angle tools on same slice to avoid…

[Belbin-GK]

Context

• Loading an SR that contains multiple angle tools on the same slice can cause a runtime error (e.g., “Something went wrong”) when scrolling through slices.

Changes & Results

• Added a guard to handle cases where image data is not available
• Avoids runtime errors when image is undefined or null
• Improves stability when loading measurement sets with multiple angle tools
• Prevents failures during slice scrolling

• Before Fix

2724-.Before.fix.mp4

• After fix

2724-.After.fix.mp4

Testing

• Launch the study with an existing SR that contains two angle tools on the same slice
• Load the SR
• Scroll through the slice containing multiple angle tools

Checklist

PR

• My Pull Request title is descriptive, accurate and follows the
  semantic-release format and guidelines.

Code

• My code has been well-documented (function documentation, inline comments,
  etc.)

Public Documentation Updates

• The documentation page has been updated as necessary for any public API
  additions or removals.

Tested Environment

• "OS: Windows 11
• "Node version: 22.20.0
• "Browser: Chrome 147.0.7727.138

[claude]

Claude Code Review

This pull request is from a fork — automated review is disabled. A repository maintainer can comment @claude review to run a one-time review.

[sen-trenser]

@wayfarer3130 Could you please take a look at this PR and provide your feedback?
Thanks!