LocalBackgroundTextMeasurementExecutor examples in foundation

CompositionLocal that provides an Executor for background text processing to potentially get run on.

BackgroundTextMeasurementSample

@Sampled
@Composable
fun BackgroundTextMeasurementSample() {
    CompositionLocalProvider(
        LocalBackgroundTextMeasurementExecutor provides DefaultTextMeasurementExecutor
    ) {
        BasicText("Hello World!")
    }
}