an analysis of the graph determines that it is safe to run.
    *   Add new enum value `MLIR_BRIDGE_ROLLOUT_SAFE_MODE_FALLBACK_ENABLED'
        to`tf.config.experimental.mlir_bridge_rollout` to enable a fallback for
        the MLIR bridge in a \"safe\" mode. This runs the MLIR bridge in a
        FallbackEnabled mode when an analysis of the graph determines that the
        graph does not have unsupported features.