[Feat] bStats Sponge Support

[Bram1903]

Overview

This pull request introduces bStats support for the Sponge platform and updates the bStats version for all other modules within PacketEvents. While updating my AntiHealthIndicator plugin to support Sponge (thanks to PacketEvents adding support), I noticed that PacketEvents lacked bStats integration for Sponge and was also using an outdated bStats version in other modules. This PR addresses both issues.

Changes

• [x] Added bStats support for Sponge.
• [x] Updated bStats version across all modules.
• [x] Switched to shading bStats via Gradle, instead of copying the Metrics class into the codebase.
• [x] Refactored Velocity's bStats initialization to use dependency injection, which is in line with recent changes in the bStats velocity class.
• [x] Moved the Sponge Gradle plugin version specification from build.gradle.kts to libs.versions.toml for better dependency management.
• [x] Adjusted the placement of the plugin started debug message in the Velocity module to occur when the plugin is actually initialized.

[Bram1903]

Although there should be a note next release that internal bstats classes were removed

Yeah, I agree. I have to update my plugins as well, but I will keep making use of these shaded classes ;-)

[Bram1903]

@retrooper, can you review this PR?

[retrooper]

Thank you for your PR.