v2.4.9

Fixed — Update dialog progress-bar fill height at 125%/150% scaling

Fast-follow to 2.4.8. Now that the Update dialog correctly scales its window at high
DPI, the download/checking progress fill was still sized to a hardcoded 18px height
while the surrounding bar scaled (≈27px at 150%), leaving the green fill short of the
bar's interior. The fill now tracks the bar's realized height at any scale. Also
corrected a stale comment that implied AutoScaleMode.Dpi scales a manually-assigned
ClientSize (it doesn't — the size is pinned in OnLoad).

Full Changelog: v2.4.8...v2.4.9