wlr_layer_shell_surface::set_size does not respect 0-sized widths and heights properly

[mattkae]

According to the wlr layer shell protocol specification:

If you pass 0 for either value, the compositor will assign it and inform you of the assignment in the configure event. You must set your anchor to opposite edges in the dimensions you omit; not doing so is a protocol error. Both values are 0 by default.

reference: https://wayland.app/protocols/wlr-layer-shell-unstable-v1#zwlr_layer_surface_v1:request:set_size

Instead, this value appears to remain 0 such that when we hit BasicWindowManager::validate_modification_request we fail validation, which results in an error.

This error was encountered when running cosmic-panel.

[AlanGriffiths]

Good find! That makes sense of what we've been seeing!

[AlanGriffiths]

Mentioning #3675 and #3676: this might make them moot, but they may also contain parts of the right behaviour.