feat(nifti): update nifti-reader-js to 0.6.8

[yanqzsu]

Context

Update nifti-reader-js from 0.6.6 to 0.6.8 because it supports to read files with corrupt extension.
Test data is here.
https://github.com/neurolabusc/niivue-images/blob/main/chris_MRA.nii.gz

Changes & Results

Testing

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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[sedghi]

Thank you so much for pushing on the nifti side, i will review this and merge your other PR today