back button functionality

[tanvidadu]

Description (required)

Fixes #1510

Pressing "Back" in zoom goes back to ShareActivity.

Tests performed (required)

Tested on betaDebug.

[codecov-io]

Codecov Report

Merging #1517 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master   #1517      +/-   ##
=========================================
- Coverage    3.86%   3.85%   -0.01%     
=========================================
  Files         151     151              
  Lines        7587    7595       +8     
  Branches      710     711       +1     
=========================================
  Hits          293     293              
- Misses       7277    7285       +8     
  Partials       17      17

Impacted Files	Coverage Δ
...java/fr/free/nrw/commons/upload/ShareActivity.java	0% <0%> (ø)	⬆️

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[misaochan]

Oops, I'm currently halfway through #1091 , which includes tidying up the zoom code. Would it be okay to hold off on merging this until that has been merged? I think it would be better to add this to a tidier ShareActivity, rather than the other way around. :)

[tanvidadu]

No problem ! :)

[maskaravivek]

@tanvidadu Can you resolve the merge conflicts for this PR. This can be tested and merge after that.

[tanvidadu]

@maskaravivek I have resolved the merge conflicts !

[misaochan]

Thanks for your patience with the refactor, @tanvidadu . :)