community/wireplumber: upgrade to 0.4.15

Changes

Additions:

A new "DSP policy" module has been added; its purpose is to automatically
load a filter-chain when a certain hardware device is present, so that
audio always goes through this software DSP before reaching the device.
This is mainly to support Apple M1/M2 devices, which require a software
DSP to be always present
WpImplModule now supports loading module arguments directly from a SPA-JSON
config file; this is mainly to support DSP configuration for Apple M1/M2
and will likely be reworked for 0.5
Added support for automatically combining Bluetooth LE Audio device sets
(e.g. pairs of earbuds) (!500)
Added command line options in wpctl to display device/node names and
nicknames instead of descriptions
Added zsh completions file for wpctl

The device profile selection policy now respects the device.profile
property if it is set on the device; this is useful to hand-pick a profile
based on static configuration rules (alsa_monitor.rules)

Changes/Fixes:

Linking policy now sends an error to the client before destroying the node,
if it determines that the node cannot be linked to any target; this fixes
error reporting on the client side
Fixed a crash in suspend-node that could happen when destroying virtual
sinks that were loaded from another process such as pw-loopback (#467)
Virtual machine default period size has been bumped to 1024 (#507)
Updated bluez5 default configuration, using bluez5.roles instead of
bluez5.headset-roles now (!498)
Disabled Bluetooth autoconnect by default (!514)
Removed RestrictNamespaces option from the systemd services in order to
allow libcamera to load sandboxed IPA modules (#466)
Fixed a JSON encoding bug with empty strings (#471)
Lua code can now parse strings without quotes from SPA-JSON
Added some missing \since annotations and made them show up in the
generated gobject-introspection file, to help bindings generators