Update text input and input method protocols

Update zwp_text_input_v3 from wayland-protocols and zwp_input_method_v2 from wlroots (as wlroots seems to be the most official place to get zwp_input_method_v2).

The zwp_text_input_v3 change is just comments but zwp_input_method_v2 changes in a breaking way. The new version adds a new interface instead of using wl_keyboard. Since Squeekboard doesn't use the grab keyboard functionality it seems the mismatch between it and wlroots wasn't causing any problems. However, it's probably a bad idea to have incompatible protocols with the same name floating around.