Fix and use MoveToPregraspCommand

[hello-binit]

The move to pregrasp method in remoterobot.tsx is defined:

moveToPregrasp(scaled_x: number, scaled_y: number, horizontal: boolean) {
    let cmd: MoveBaseCommand = {
        type: "moveToPregrasp",
        scaled_x: scaled_x,
        scaled_y: scaled_y,
        horizontal: horizontal,
    };
    this.robotChannel(cmd);
}

cmd is of type MoveBaseCommand, but should be MoveToPregraspCommand. In commands.tsx, the interface is defined:

export interface MoveToPregraspCommand {
    type: "moveToPregrasp";
    x: number;
    y: number;
}

x should be scaled_x, y should scaled_y, and horizontal is missing.

It doesn't really matter that the interface is incorrect / not used, because the robot browser interprets the object correctly, but for clarity's sake, it's worth correcting the interface and using the type. Low priority.