BridgeJS: support imports of JS `Promise` as `async` Swift #2511

Job	Run time
check-bridgejs-generated	2m 47s
format	34s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	3m 0s
Build for native target (macos-15, Xcode_16.4)	3m 51s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	15m 54s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	13m 10s
prettier	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/swift-6.1-release/ubuntu2204/swift-6.1-R...	13m 42s
build-examples	19m 50s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	2m 56s
deploy-examples	-1s
	1h 28m 37s

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