Fix T65763: Reset GPU when exporting annotations

When exporting annotations using `bpy.ops.render.opengl` the annotations
where only correct in the first frame. In the second frame the
annotations was shifted by half the resolution.

This change will reset the GPU matrices when the annotations are
rendered.

source/blender/editors/render/render_opengl.c

@@ -331,6 +331,7 @@ static void screen_opengl_render_doit(const bContext *C, OGLRender *oglrender, R
       GPU_clear_color(0.0f, 0.0f, 0.0f, 0.0f);
       GPU_clear(GPU_COLOR_BIT | GPU_DEPTH_BIT);
 
+      GPU_matrix_reset();
       wmOrtho2(0, scene->r.xsch, 0, scene->r.ysch);
       GPU_matrix_translate_2f(scene->r.xsch / 2, scene->r.ysch / 2);