🍒 checkbox: Apply indeterminate after checked

An "inconsistent" (indeterminate) checkbox is still "checked" as far as GTK is concerned. Breeze shares the indeterminate state between radio and check. Therefore, the individual checked state overwrote the indeterminate state before.

Applying indeterminate afterwards fixes this and is consistent with what Adwaita does.

Signed-off-by: Sebastian Stark sebastian.stark@advantest.com (cherry picked from commit ac47aade)