bugfix: fixed bug in image-picker, Uncaught TypeError: Cannot set pro…

[dqmmpb]

Fixed a bug in image-picker, Uncaught TypeError: Cannot set property 'value' of null.

When the selector at the header of a new row, then delete a pic, and readd a new pic, the bug appear. So, do not delete the fileselectorInput, if the input is null.

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This change is 

[codecov]

Codecov Report

Merging #2302 into master will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2302      +/-   ##
==========================================
- Coverage   57.63%   57.61%   -0.03%     
==========================================
  Files         260      260              
  Lines        4464     4466       +2     
  Branches     1178     1179       +1     
==========================================
  Hits         2573     2573              
- Misses       1890     1892       +2     
  Partials        1        1

Flag	Coverage Δ
#rn	60.78% <ø> (ø)	⬆️
#web	54.91% <ø> (-0.05%)	⬇️

Impacted Files	Coverage Δ
components/image-picker/index.tsx	33.02% <ø> (-0.62%)	⬇️

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