break the sp lighting loop early in modern gl(es)

[riccardobl]

In modern GL(es) there is no point in wasting gpu power processing the whole light batch, this PR stops it as soon as all the active lights are processed, when the shader is compiled in GLES3+ or GL 3.2+.
To integrate this cleanly while also keeping backward compatibility, a new g_LightCount uniform is added.

[gemini-code-assist]

Summary of Changes

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This pull request introduces a performance optimization for lighting calculations in modern OpenGL (GL 3.2+) and OpenGL ES (GLES 3+) by terminating the lighting loop early once all active lights have been processed. This avoids unnecessary GPU processing and improves rendering efficiency. The changes involve modifying shader code and updating light list uniforms to pass the number of active lights to the shader.

Highlights

• Performance Optimization: This PR optimizes shader performance in modern OpenGL and OpenGL ES by breaking the lighting loop early when all active lights have been processed.
• Conditional Compilation: The changes are conditionally compiled based on the OpenGL ES version (3.0+) or OpenGL version (3.2+), ensuring compatibility with older versions.
• Uniform Update: A new uniform, g_LightCount, is introduced to track the number of active lights, which is then used to control the early exit from the lighting loop.

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[gemini-code-assist]

Code Review

This pull request introduces a performance optimization for single-pass lighting by breaking out of the light processing loop early in shaders when not all light slots are used. This is achieved by introducing a new g_LightCount uniform. The changes are implemented for modern GL and GLES versions while maintaining backward compatibility. The logic appears sound and correctly implemented across the relevant Java logic classes and shader files. I have one suggestion to improve maintainability by abstracting the duplicated shader code into a macro.