Fix ResultCollection._get_cache with multielement tensors

[carmocca]

What does this PR do?

Fixes #9528

Does your PR introduce any breaking changes? If yes, please list them.

None

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[codecov]

Codecov Report

Merging #9582 (360bdcb) into master (bbcb977) will increase coverage by 3%.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master   #9582    +/-   ##
=======================================
+ Coverage      89%     92%    +3%     
=======================================
  Files         181     181            
  Lines       15245   15728   +483     
=======================================
+ Hits        13549   14445   +896     
+ Misses       1696    1283   -413     

[tchaton]

Great catch !

[ethanwharris]

LGTM 😃