fix: ignore invalid commands before applying cooldown (closes #6573)

[RomainCabaret]

Information

This PR fixes #6573 .

Details

Proposed fix:
Check whether the exact raw command label typed by the player exists in the server's registered commands (via KnownCommandsProvider) before applying a cooldown in EssentialsPlayerListener.

Under Brigadier (1.13+), command matching is case-sensitive, meaning capitalized aliases such as /FEED or /EFEED are rejected by the server as unknown commands. Previously, EssentialsX converted the command to lowercase early and still applied the configured cooldown despite the command failing to execute. With this check, unknown or incorrectly capitalized commands are ignored by the cooldown handler and will not unfairly consume the player's cooldown.

Environments tested:

OS: Fedora Linux
Java version: OpenJDK 21

• Most recent Paper version (26.2)
• CraftBukkit/Spigot/Paper 1.12.2
• CraftBukkit 1.8.8

Demonstration:

[mdcfe]

This approach would fundamentally break command alias plugins that inject themselves at the pre-process event level. While that isn't something we'd generally support (aliases should really be registered to the command map and Brigadier in 2026), I'm hesitant to potentially break existing alias setups here.

[RomainCabaret]

Sorry about that, I hadn't considered custom alias plugins hooking in at the preprocess level.

The issue with #6573 is that Essentials applies cooldowns case-insensitively, even when Brigadier later rejects the command due to strict case sensitivity (e.g. /FEED).

How would you prefer to handle this without breaking alias plugins? Should we only apply this check to commands registered by EssentialsX itself, or handle it differently?