docs(block-ui): update stories for BlockUI

[ncruz-av]

Before submitting a pull request, please make sure the following is done:

1. Fork the repository and create your branch from master.
2. Run yarn in the repository root.
3. If you've fixed a bug or added code that should be tested, add tests!
4. Ensure the test suite passes (yarn test). Tip: yarn test --watch TestName is helpful in development.
5. Make sure your code passed the conventional commits check. Read more about conventional commits

[codecov[bot]]

Codecov Report

Merging #1317 (3b082a8) into master (108376a) will decrease coverage by 0.83%. Report is 27 commits behind head on master. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1317      +/-   ##
==========================================
- Coverage   92.11%   91.29%   -0.83%     
==========================================
  Files         188       31     -157     
  Lines        5290      827    -4463     
  Branches     1603      265    -1338     
==========================================
- Hits         4873      755    -4118     
+ Misses        417       72     -345     

see 157 files with indirect coverage changes