kwinrules: Do not force suggested property values
This is unnecessary and also causes a bug, overwriting
previously set properties with the new detected values
when calling for the menu Edit window properties
.
To reproduce:
- On any app:
Alt-F3
->Edit Window Properties...
- Add some properties (position/size) and apply
- Move and resize the app
- Again on the same app:
Alt-F3
->Edit Window Properties...
While at it, change signal name to better match its meaning (on a second commit, it can be squashed at will)