fix: clipping not working properly

[davidetan]

This PR fixes a couple of problem with clipping:

• clipping was not always attempted to be ended
• when spinePipe.addRenderable is called with a cacheData.clippedData.vertexCount set at 0, but cacheData.clippedData.vertices.length is bigger than 0, it was still added to the batch, generating a GL_INVALID_OPERATION: Insufficient buffer size. on webgl and a Calling [RenderPassEncoder (unlabeled)].Draw with an index count of 0 is unusual. on webgpu
• when spinePipe.updateRenderable is called, the batcher.updateElement was called regardless of the fact the attachment has zero clipped vertices to draw; however, the vertexSize of the BatchableSpineSlot is never set to zero becuase addRenderable set it only if vertices are more than zero. I added an if into updateRenderable, otherwise we can move the batchableSpineSlot.setData outside the if in the addRenderable
• Removed a useless clipper from the SpinePipe

I'm not an expert of RenderPipe, so let me know if I did some wrong assumption :)

[GoodBoyDigital]

hey @davidetan , do you have a spine file i could use to test this pls? I think there might be a way we can avoid the extra checks in addRenderable but would like to verify! thanks man

[davidetan]

hey @davidetan , do you have a spine file i could use to test this pls? I think there might be a way we can avoid the extra checks in addRenderable but would like to verify! thanks man

Sure, just use the basic example and change the animation from run to portal at this line: https://github.com/pixijs/spine-v8/blob/main/examples/basic.html#L45

[davidetan]

Close in favor of this: #32