BridgeJS: support imports of JS `Promise` as `async` Swift #2529

Job	Run time
format	56s
check-bridgejs-generated	2m 35s
prettier	47s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	3m 11s
Build for native target (macos-15, Xcode_16.4)	2m 3s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	3m 5s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	3m 43s
build-examples	3m 43s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	3m 41s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	3m 39s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	3m 43s
deploy-examples	1s
	31m 7s

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