update adwaita-icon-theme to 44.0

@smcv There is a new 44.0 release of adwaita-icon-theme

In this release, many full-color icons are only supplied as 16x16 and scalable. We supply 24x24 and 48x48 icons for our legacy 41 icon set. Does it make sense to switch those to 16x16 too? On the other hand, there were changes made to some of the 16x16 icons in the 44.0 release to ensure that those look good; that work was never done for the 41 series.

Here's the adwaita-icon-theme-44.debdiff. It looks reasonable to me so I guess it would be ok to keep the 41 set as is. What do you think?

After we land this update, we should land the 45.beta update. The biggest change is that it switches to meson. I don't think that causes us any issues.