fix: actaully reset 'injectedKeys'

[mroderick]

Re-assigning the local variable injectedKeys would not change sandbox.injectedKeys, thus restoreContext doesn't fully restore the context.

See:

https://lgtm.com/projects/g/sinonjs/sinon/snapshot/9e09e7d79bac5808ca98fac4f7419a20be4fc43d/files/lib/sinon/sandbox.js?sort=name&dir=ASC&mode=heatmap#x9f770d565ef51b7d:1

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01 ⚠️

Comparison is base (3b41aff) 95.99% compared to head (98cffd0) 95.99%.

❗ Current head 98cffd0 differs from pull request most recent head 804d691. Consider uploading reports for the commit 804d691 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2456      +/-   ##
==========================================
- Coverage   95.99%   95.99%   -0.01%     
==========================================
  Files          40       40              
  Lines        1898     1896       -2     
==========================================
- Hits         1822     1820       -2     
  Misses         76       76              

Flag	Coverage Δ
unit	95.99% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
lib/sinon/sandbox.js	97.72% <100.00%> (-0.03%)	⬇️

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[fatso83]

Any way of adding a regression test to show the bug?

[mroderick]

Any way of adding a regression test to show the bug?

That's a fair question. We haven't detected it thus far with tests and users have also not reported it.
There might be something else that resets that property, so we've been hiding in the shadow of that for years.

I can look further