BridgeJS: fix codegen for async + throws exported methods (#691) #2447

Job	Run time
build-examples	21m 5s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	3m 5s
check-bridgejs-generated	2m 54s
format	37s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	13m 29s
prettier	8s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	13m 29s
Build for native target (macos-15, Xcode_16.4)	5m 46s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	3m 9s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	12m 45s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	16m 41s
deploy-examples	10s
	1h 33m 18s

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