Fix get all albums from cached results

[mib1185]

We extended the first result with the second one, but as the first result comes from the cache, the cache object got extended every time and those duplicated the shared albums into it.

ref. home-assistant/core#169866

[Copilot]

Pull request overview

Fixes a bug where the cached non-shared albums list was being mutated by list.extend(), causing shared albums to be appended repeatedly across calls and resulting in duplicates.

Changes:

• Replace in-place result.extend(result_shared) with a new-list concatenation result + result_shared to avoid mutating the cached result.

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.28%. Comparing base (00b54a4) to head (aa2b8c5).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #52      +/-   ##
==========================================
- Coverage   96.28%   96.28%   -0.01%     
==========================================
  Files          17       17              
  Lines         485      484       -1     
==========================================
- Hits          467      466       -1     
  Misses         18       18              

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