fix(pf3): stop date picker crash when value is string.

[Hyperkid123]

closes #189

Day picker can now accept value as a string.

[rvsia]

@Hyperkid123 Could you please write a little test? Thanks! 🌮

[Hyperkid123]

ups forgot add the WIP thing Working on it right now.

[codecov-io]

Codecov Report

Merging #191 into master will increase coverage by 1.28%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #191      +/-   ##
==========================================
+ Coverage   81.74%   83.03%   +1.28%     
==========================================
  Files          87       87              
  Lines        1397     1397              
  Branches      344      344              
==========================================
+ Hits         1142     1160      +18     
+ Misses        211      197      -14     
+ Partials       44       40       -4

Impacted Files	Coverage Δ
...c/form-fields/date-time-picker/date-time-picker.js	64.7% <ø> (+52.94%)	⬆️

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[skateman]

Now it's throwing me Invalid Date if the initialValue is not set:

{
  "component": "date-picker",
  "name": "date-picker-1",
  "label": "Datepicker 1",
  "visible": true,
  "disabledDays": [
    {
      "before": "today"
    }
  ],
  "variant": "date"
}

And by clicking on the picker icon, it crashes with Cannot read property 'length' of undefined

[Hyperkid123]

@skateman ah there is one mor thing i forgot

[skateman]

[rvsia]

@Hyperkid123 what about to add a test that proves that picker icon click crash is gone, just to be sure it won't be repeated in the future? Otherwise looks good!

[Hyperkid123]

@rvsia the crash has nothing to do with the clicl but with the fact the it was sending string to the day picker component instead of Date object.