Update texture crash fix

examples/minimal/minimal.odin

@@ -29,7 +29,6 @@ main :: proc() {
 	k2.init(1080, 1080, "Karl2D Minimal Program")
 	k2.set_window_position(300, 100)
 	tex := k2.load_texture_from_file("sixten.jpg")
-	k2.set_texture_filter(tex, .Point)
 
 	for !k2.shutdown_wanted() {
 		k2.process_events()

render_backend_d3d11.odin

@@ -396,7 +396,7 @@ d3d11_load_texture :: proc(data: []u8, width: int, height: int, format: Pixel_Fo
 d3d11_update_texture :: proc(th: Texture_Handle, data: []u8, rect: Rect) -> bool {
 	tex := hm.get(&s.textures, th)
 
-	if tex == nil {
+	if tex == nil || tex.tex == nil {
 		return false
 	}