Fixed null scenario for downloadItem

[NejcZdovc]

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.

Resolves #10223

Auditors: @bsclifton

Test Plan:

• covered with automated tests

Reviewer Checklist:

Tests

• Adequate test coverage exists to prevent regressions
• Tests should be independent and work correctly when run individually or as a suite ref
• New files have MPL2 license header

[codecov-io]

Codecov Report

Merging #10225 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master   #10225      +/-   ##
==========================================
- Coverage   52.93%   52.93%   -0.01%     
==========================================
  Files         228      228              
  Lines       20295    20297       +2     
  Branches     3251     3252       +1     
==========================================
  Hits        10744    10744              
- Misses       9551     9553       +2

Flag	Coverage Δ
#unittest	52.93% <0%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
app/browser/electronDownloadItem.js	40.81% <0%> (-1.74%)	⬇️