Preview component should not rely on prop change detection to send expressions to frame

Currently the <Preview> component looks for changes in the list of console expressions to determine what if any expressions to send to the frame for evaluation. Component behavior that depends on both previous and current state is considerably harder to reason about and should be avoided. Instead, console entries should have state indicating whether they have been sent to a frame for evaluation; this should be updated synchronously after the frame initially posts the expression. The <Preview> component should simply consume all entries that are not marked as evaluation started.

Empieza siguiendo el componente y el console-entry state que se utiliza cuando el frame publica una expresión por primera vez. Identifica dónde se marcan las entradas después de que comienza la evaluación y, a continuación, actualiza el flujo para que Preview consuma las entradas que no estén marcadas como iniciadas. Se considera terminado cuando la entrega de la expresión ya no depende de comparar los valores de props anteriores y actuales.