Use cosmic-text shaping buffer (#14991)

# Objective

- Improve performance of `cosmic-text` integration.

## Solution

- Activate the `shape-run-cache` feature to improve amortized cost of
spawning/updating text.

crates/bevy_text/Cargo.toml

@@ -29,7 +29,7 @@ bevy_window = { path = "../bevy_window", version = "0.15.0-dev" }
 bevy_utils = { path = "../bevy_utils", version = "0.15.0-dev" }
 
 # other
-cosmic-text = "0.12"
+cosmic-text = { version = "0.12", features = ["shape-run-cache"] }
 thiserror = "1.0"
 serde = { version = "1", features = ["derive"] }
 unicode-bidi = "0.3.13"