proper class on avatar when image doesnt exist

[andriijas]

When Avatar is rerendered because the image didnt exist, wrong class is applied today which makes the background transparent for Icon or text. This PR fixes that.

Thanks

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[codecov]

Codecov Report

Merging #9278 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #9278      +/-   ##
==========================================
+ Coverage   85.85%   85.85%   +<.01%     
==========================================
  Files         195      195              
  Lines        4615     4616       +1     
  Branches     1283     1284       +1     
==========================================
+ Hits         3962     3963       +1     
  Misses        649      649              
  Partials        4        4

Impacted Files	Coverage Δ
components/avatar/index.tsx	94.73% <100%> (+0.14%)	⬆️

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