fix(schema-compiler): ExportNamedDeclaration for variables object

[KSDaemon]

This supersedes the original PR by @arkadiusz-swierczek-pm with some improvements/fixes.

Check List

• Tests have been run in packages where changes made if available
• Linter has been run for changed code
• Tests for the changes have been added if not covered yet
• Docs have been added / updated if required

Closes #8774

[ovr]

Fix LGTM, but any kind of test is required!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 47.97%. Comparing base (14ae6a4) to head (58aa81e).
Report is 4 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (14ae6a4) and HEAD (58aa81e). Click for more details.

HEAD has 2 uploads less than BASE

Flag	BASE (14ae6a4)	HEAD (58aa81e)
cubesql	2	0

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #9390       +/-   ##
===========================================
- Coverage   76.57%   47.97%   -28.60%     
===========================================
  Files         400      171      -229     
  Lines      105044    21424    -83620     
  Branches     3707     3710        +3     
===========================================
- Hits        80434    10279    -70155     
+ Misses      24174    10706    -13468     
- Partials      436      439        +3     

Flag	Coverage Δ
cube-backend	47.97% <100.00%> (+0.11%)	⬆️
cubesql	?

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