fix: pass entities arg to WASM visualization/dashboard converters

[jaceksan]

Summary

declarative_visualization_to_aac and declarative_dashboard_to_aac were passing only the declarative dict to the WASM converters, but the TS functions declarativeVisualisationToYaml(entities, visualisation) and declarativeDashboardToYaml(entities, dashboard) expect entities as the first argument. The dict was received as entities, leaving the actual object undefined — causing "cannot read property 'content' of undefined" for every visualization and dashboard during get_and_store_aac_workspace.

Test plan

• New unit tests for declarative→AAC visualization conversion (fixture round-trip and inline)
• New integration test: store_aac_workspace_to_disk with visualizations, then reload
• New integration test: full fixture load→store→reload round-trip
• All 23 AAC tests pass

Co-authored-by: Claude Opus 4.6 (1M context) noreply@anthropic.com
JIRA: DX-326
risk: low

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.18%. Comparing base (d6a7ef4) to head (48dc249).

Files with missing lines	Patch %	Lines
...data-sdk/src/gooddata_sdk/catalog/workspace/aac.py	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1514      +/-   ##
==========================================
+ Coverage   78.13%   78.18%   +0.04%     
==========================================
  Files         228      228              
  Lines       14926    14928       +2     
==========================================
+ Hits        11662    11671       +9     
+ Misses       3264     3257       -7     

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