fix(engine): cleanup leaked context

[fgimenez]

After the introduction on std::thread::scope for creating StateRootTask, we started using Box::leak to keep alive values required to return and move around the state hook closure. The changes in this PR clean up the leaked data after it has been used, will prevent warnings like:

WARN Long-lived read transaction has been timed out

[shekhirin]

This works

[codspeed-hq]

CodSpeed Performance Report

Merging #13749 will degrade performances by 15.18%

_{Comparing fgimenez/cleanup-leaked-context (227dc8b) with main (567d5c6)}

Summary

❌ 4 regressions
✅ 73 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	fgimenez/cleanup-leaked-context	Change
❌	hash builder[init size 10000 | update size 100 | num updates 10]	84.1 ms	94.2 ms	-10.69%
❌	hash builder[init size 10000 | update size 100 | num updates 1]	9 ms	10.6 ms	-15.18%
❌	hash builder[init size 10000 | update size 100 | num updates 3]	26.8 ms	30.6 ms	-12.33%
❌	hash builder[init size 10000 | update size 100 | num updates 5]	43.8 ms	50.7 ms	-13.66%