GLES3: Fix regression in particles buffer initialization

Bug introduced in #26343 where `(float *)` was mistakenly converted
to `(uint8_t *)`, so we were getting `2` instead of `8`.

Fixes #27705.

(cherry picked from commit b182e038e763efbb68ed8839351e01a20d24984d)

drivers/gles3/rasterizer_canvas_gles3.cpp

@@ -2043,7 +2043,7 @@ void RasterizerCanvasGLES3::initialize() {
 		glEnableVertexAttribArray(VS::ARRAY_VERTEX);
 		glVertexAttribPointer(VS::ARRAY_VERTEX, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 4, 0);
 		glEnableVertexAttribArray(VS::ARRAY_TEX_UV);
-		glVertexAttribPointer(VS::ARRAY_TEX_UV, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 4, CAST_INT_TO_UCHAR_PTR(2));
+		glVertexAttribPointer(VS::ARRAY_TEX_UV, 2, GL_FLOAT, GL_FALSE, sizeof(float) * 4, CAST_INT_TO_UCHAR_PTR(8));
 		glBindVertexArray(0);
 		glBindBuffer(GL_ARRAY_BUFFER, 0); //unbind
 	}

drivers/gles3/rasterizer_storage_gles3.cpp

@@ -6080,7 +6080,7 @@ void RasterizerStorageGLES3::particles_set_amount(RID p_particles, int p_amount)
 
 		for (int j = 0; j < 6; j++) {
 			glEnableVertexAttribArray(j);
-			glVertexAttribPointer(j, 4, GL_FLOAT, GL_FALSE, sizeof(float) * 4 * 6, CAST_INT_TO_UCHAR_PTR((j * 16)));
+			glVertexAttribPointer(j, 4, GL_FLOAT, GL_FALSE, sizeof(float) * 4 * 6, CAST_INT_TO_UCHAR_PTR(j * 16));
 		}
 	}