fix: Short-circuit fetch on insert

[sfc-gh-rnarubin]

What's changed and what's your intention?

Please explain IN DETAIL what the changes are in this PR and why they are needed. :D

There was a bug in the inflight tracking where the close boolean was duplicated instead of cloned. This could result in fetch futures running in the background even though all the waiters were already resolved.

Checklist

• I have written the necessary rustdoc comments
• I have added the necessary unit tests and integration tests
• I have passed cargo x (or cargo x --fast instead if the old tests are not modified) in my local environment.

Related issues or PRs (optional)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

❗ There is a different number of reports uploaded between BASE (481c3de) and HEAD (9e81479). Click for more details.

HEAD has 2 uploads less than BASE

Flag	BASE (481c3de)	HEAD (9e81479)
	3	1

Files with missing lines	Coverage Δ
foyer-memory/src/inflight.rs	62.80% <100.00%> (-27.28%)	⬇️
foyer-memory/src/raw.rs	49.42% <ø> (-37.98%)	⬇️

... and 52 files with indirect coverage changes

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