Verso combat: Override less of throwing_enemy.gd

[wjt]

Previously throwing_enemy_health.gd overrode shoot_projectile() with two changes:

1. It adjusts the distance from the enemy that the projectile spawns;
2. It sets can_hit_enemy = true on the projectile.

Since this scene was first written, it has become possible to adjust
both of these properties.

Make a copy of the projectile, verso_projectile.tscn, which sets
can_hit_enemy to true.

Adjust ThrowingEnemyHealth.tscn to use this copy of the projectile, and
to set the distance to 75.

Delete the shoot_projectile() override.

Resolves #1316

[github-actions]

Play this branch at https://play.threadbare.game/branches/endlessm/wjt/verso-combat-override-less-of-throwing-enemy-gd.

(This launches the game from the start, not directly at the change(s) in this pull request.)

[wjt]

I'm going to merge this because I am refactoring the projectile-spawning logic.