BridgeJS: Correctly emit @JS methods in extensions #2458

Job	Run time
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	3m 43s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	3m 12s
build-examples	19m 7s
Build for native target (macos-15, Xcode_16.4)	1m 55s
check-bridgejs-generated	2m 50s
prettier	13s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	1s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	3m 11s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	1s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	1s
format	32s
deploy-examples	0s
	34m 46s

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