www/palemoon: Consolidate sndio patches and apply softvol fix [1]

This will prevent Pale Moon from changing the slot volumes of sndiod
which can lead to them being too silent or even muted when Pale Moon
happens to reuse one of them later. It'll also fix a bug where Pale
Moon won't pick up slot volumes changes done externally and thus
provides inaccurate volume controls.

[1] https://marc.info/?l=openbsd-ports&m=152641946326955&w=2

PR: 228479
Submitted by: tobik
Approved by: lichray@gmail.com (maintainer)