BridgeJS: support imports of JS `Promise` as `async` Swift #2516

Job	Run time
check-bridgejs-generated	2m 52s
Build for native target (macos-15, Xcode_16.4)	2m 6s
prettier	10s
format	40s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	9m 32s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	9m 28s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	2m 59s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	9m 26s
build-examples	9m 26s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	3m 24s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	9m 26s
deploy-examples	1s
	59m 30s

Provide feedback