Handle null URI while uploading picture

[maskaravivek]

Description (required)

Fixes #2033

What changes did you make and why?

Have started handling null URI from the received intent. It should fix the issue @misaochan was facing. There can be other reasons for app getting stuck at this step. We can keep an eye on the reports and fix those issues as well.

[codecov-io]

Codecov Report

Merging #2262 into master will increase coverage by <.01%.
The diff coverage is 29.41%.

@@            Coverage Diff            @@
##           master   #2262      +/-   ##
=========================================
+ Coverage    6.35%   6.36%   +<.01%     
=========================================
  Files         233     233              
  Lines       11570   11585      +15     
  Branches     1065    1069       +4     
=========================================
+ Hits          735     737       +2     
- Misses      10773   10785      +12     
- Partials       62      63       +1

Impacted Files	Coverage Δ
...a/fr/free/nrw/commons/upload/FileUtilsWrapper.java	42.85% <0%> (+5.35%)	⬆️
...ain/java/fr/free/nrw/commons/upload/FileUtils.java	10.41% <0%> (-0.28%)	⬇️
...ava/fr/free/nrw/commons/upload/UploadActivity.java	0% <0%> (ø)	⬆️
...n/java/fr/free/nrw/commons/upload/UploadModel.java	60.09% <66.66%> (+0.38%)	⬆️
...in/java/fr/free/nrw/commons/utils/StringUtils.java	0% <0%> (ø)	⬆️

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