Prevent layer shells to go crazy if they set massively attributes
This is a follow up of : https://github.com/swaywm/sway/pull/6709
This commit try to fix a case we encounter when running wayout, a layer shell to display text above the background.
When running wayout, other layer shell start to consume 100% of the CPU.
Our understanding is that wayout massively set attributes (that are the same than the old ones) and that cause a chain loop of re-aranging behavior in sway.
To fix this issue, we ensure the new attribute value differ from the current one before preparing a pending state.
Edited by Willow