Implement native http.fetchOhttpKeys in dart

[spacebear21]

Addresses #1362 for Dart

Authored by Claude Opus 4.7

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[coveralls]

Coverage Report for CI Build 24680141516

Coverage remained the same at 84.502%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	12924
Covered Lines:	10921
Line Coverage:	84.5%
Coverage Strength:	408.5 hits per line

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💛 - Coveralls

[benalleng]

TACK b8d6524

I brought it up in #1489 for the rust side but is making a sync version in these language bindings useful or practical at all?

[spacebear21]

is making a sync version in these language bindings useful or practical at all?

From my experience it seems like downstream languages have mostly needed async where we offer only sync, I don't recall seeing it the other way around. I'm open to it if there's real demand for it.