flatpak: Only ignore estimated progress if >10%

Flatpak may set the "estimating" flag on a progress report if the value is bogus, or it may set it if it is downloading metadata which it arbitrarily decides comprises the first 5% of an install operation. Ignoring estimated progress therefore means we get no progress changes for the first 10% of an app install (installing the app and its locale extension). Instead, only ignore the estimated progress if it is an obviously bogus value of >10%.