Drop Embedded Swift with 6.1 and earlier and remove `JAVASCRIPTKIT_EXPERIMENTAL_EMBEDDED_WASM` #1911

Job	Run time
build-examples	23s
format	33s
check-bridgejs-generated	21s
Build for native target (macos-15, Xcode_16.4)	1m 31s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	3m 19s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	3m 4s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	3m 19s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	3m 19s
deploy-examples	0s
	15m 49s

Provide feedback