Add UI to modify `FontTweak` live (#5125) #12758

Job	Run time
Format + check + test	5m 35s
cargo-deny aarch64-apple-darwin	38s
Check wasm32 + wasm-bindgen	2m 13s
cargo-deny aarch64-linux-android	37s
cargo-deny i686-pc-windows-gnu	39s
Check wasm32+atomics	1m 16s
cargo-deny i686-pc-windows-msvc	40s
cargo-deny i686-unknown-linux-gnu	37s
android	21s
cargo-deny wasm32-unknown-unknown	39s
cargo-deny x86_64-apple-darwin	38s
ios	19s
cargo-deny x86_64-pc-windows-gnu	40s
Check Windows	1m 48s
cargo-deny x86_64-pc-windows-msvc	41s
cargo-deny x86_64-unknown-linux-gnu	38s
cargo-deny x86_64-unknown-linux-musl	48s
cargo-deny x86_64-unknown-redox	37s
	19m 24s

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