style(src/assets/icons/volume): switch color definitions to currentColor for theme compatibility

src/assets/icons/volume/audio-volume.svg

@@ -1,6 +1,6 @@
 <svg width="22" height="22" version="1.1" xmlns="http://www.w3.org/2000/svg">
  <defs>
-  <style id="current-color-scheme" type="text/css">.ColorScheme-Text { color:#f2f2f2; } .ColorScheme-Highlight { color:#4285f4; }</style>
+  <style id="current-color-scheme" type="text/css">.ColorScheme-Text { color:currentColor; } .ColorScheme-Highlight { color:#4285f4; }</style>
  </defs>
  <g class="ColorScheme-Text" fill="currentColor">
   <path d="m16.623 16.612c0.25079 0.16531 0.58712 0.09118 0.76949-0.18243 1.0032-1.5048 1.6075-3.3744 1.6075-5.4264 0-2.0577-0.61566-3.9216-1.6075-5.4321-0.18237-0.2793-0.5187-0.3477-0.76949-0.1824-0.27362 0.1767-0.3135 0.513-0.12536 0.8151 0.87209 1.3281 1.4136 2.9754 1.4136 4.7994 0 1.8126-0.54146 3.4713-1.4136 4.7938-0.18814 0.30209-0.14826 0.63835 0.12536 0.81508z"/>