Move the text layout demo to its own window in the demo app #6953

Job	Run time
Check wasm32 + wasm-bindgen	3m 37s
android	43s
cargo-deny aarch64-apple-darwin	3m 56s
cargo-deny aarch64-linux-android	4m 32s
cargo-deny i686-pc-windows-gnu	3m 43s
cargo-deny i686-pc-windows-msvc	3m 59s
cargo-deny i686-unknown-linux-gnu	3m 48s
cargo-deny wasm32-unknown-unknown	4m 23s
cargo-deny x86_64-apple-darwin	3m 50s
cargo-deny x86_64-pc-windows-gnu	4m 11s
cargo-deny x86_64-pc-windows-msvc	4m 9s
cargo-deny x86_64-unknown-linux-gnu	3m 58s
cargo-deny x86_64-unknown-linux-musl	3m 58s
cargo-deny x86_64-unknown-redox	4m 11s
Format + check + test	5m 46s
Check Windows	1m 48s
	1h 0m 32s

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