Addons Jest - Fix test matching

[igor-dv]

Issue: #4497

What I did

1. Changed test name matching to regex
2. When "jest" parameter is a string it should be mapped to array.

[codecov]

Codecov Report

Merging #4689 into master will decrease coverage by 0.02%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #4689      +/-   ##
==========================================
- Coverage   35.59%   35.57%   -0.03%     
==========================================
  Files         557      557              
  Lines        6732     6736       +4     
  Branches      884      886       +2     
==========================================
  Hits         2396     2396              
- Misses       3876     3878       +2     
- Partials      460      462       +2

Impacted Files	Coverage Δ
addons/jest/src/index.js	0% <0%> (ø)	⬆️

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[shilman]

LGTM. are there any tests for this?

[igor-dv]

We can see this working in preview https://deploy-preview-4689--storybooks-official.netlify.com/?selectedKind=Addons%7Cjest&selectedStory=withTests&full=0&addons=1&stories=1&panelRight=0&addonPanel=storybook%2Ftests%2Fpanel

But I will add some unit tests anyway. Maybe as a separate PR