Fix level-win duplicate handling, apply mouse-control changes immediately, and default asteroid gravity off

[jackandcarter]

Motivation

• Prevent duplicate level-win transitions by removing overlapping win logic from the asteroid manager.
• Ensure player input settings (mouse control) apply immediately to active players when toggled in the settings UI.
• Make gravitational pull off by default for classic-mode asteroids to match the intended default gameplay options.

Description

• Removed the AllAsteroidsCleared subscription and the internal delayed level-win coroutine from AsteroidManager and simplified CheckLevelWinCondition to only raise AllAsteroidsCleared when counts reach zero.
• Deleted the AreAsteroidsOnScreen and LevelWinAfterDelay helpers and removed the levelWinCoroutineStarted flag and related logic.
• Added SetMouseControlEnabled(bool) to PlayerController and used it at Awake to initialize mouseControlEnabled, with safe enabling/disabling of rightClickAction.
• Updated SettingsPanel.ToggleMouseControl to persist the preference and immediately call SetMouseControlEnabled on all active PlayerController instances, and changed LargeAsteroidBehavior to set enableGravitationalPull default to false.

Testing

• No automated tests were executed as part of this change.
• The changes were built and committed locally (no CI test results included).

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Codex Task