fix: _init function condition fault-tolerant in ScaleOverlayTool

[baokeyu123]

Context

after i destroy toolgroup and destroy renderingEngine, i recreate new toolgroup and new renderingEngine with the same id(toolgroupId).this error would happen.

Changes & Results

- else if (this.editData.annotation.data.viewportId == viewport.id)
+ else if (this.editData.annotation && this.editData.annotation.data.viewportId == viewport.id)

Testing

None

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.)

• I have run the yarn build:update-api to update the API documentation, and have
  committed the changes to this PR. (Read more here https://www.cornerstonejs.org/docs/contribute/update-api)

Public Documentation Updates

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

Tested Environment

• "OS:
• "Node version:
• "Browser:

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