Remove dead code for system VK.

ui/keyboard/resources/images/brightness-down.svg

Index: ui/keyboard/resources/images/brightness-down.svg
diff --git a/ui/keyboard/resources/images/brightness-down.svg b/ui/keyboard/resources/images/brightness-down.svg
deleted file mode 100644
index 5f5c5dc5753b00d6162b563551cde7f98ad7b6a0..0000000000000000000000000000000000000000
--- a/ui/keyboard/resources/images/brightness-down.svg
+++ /dev/null
@@ -1,34 +0,0 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<!-- Created with Inkscape (http://www.inkscape.org/) -->
-
-<svg
-   xmlns:dc="http://purl.org/dc/elements/1.1/"
-   xmlns:cc="http://creativecommons.org/ns#"
-   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
-   xmlns:svg="http://www.w3.org/2000/svg"
-   xmlns="http://www.w3.org/2000/svg"
-   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
-   version="1.1"
-   width="43.75"
-   height="26.25"
-   id="svg2"
-   xml:space="preserve"><metadata
-     id="metadata8"><rdf:RDF><cc:Work
-         rdf:about=""><dc:format>image/svg+xml</dc:format><dc:type
-           rdf:resource="http://purl.org/dc/dcmitype/StillImage" /></cc:Work></rdf:RDF></metadata><defs
-     id="defs6"><clipPath
-       id="clipPath16"><path
-         d="M 0,21 35,21 35,0 0,0 0,21 z"
-         inkscape:connector-curvature="0"
-         id="path18" /></clipPath></defs><g
-     transform="matrix(1.25,0,0,-1.25,0,26.25)"
-     id="g10"><g
-       id="g12"><g
-         clip-path="url(#clipPath16)"
-         id="g14"><g
-           transform="translate(17.5,8.5654)"
-           id="g20"><path
-             d="m 0,0 c -1.068,0 -1.934,0.868 -1.934,1.935 0,1.066 0.866,1.933 1.934,1.933 1.067,0 1.932,-0.867 1.932,-1.933 C 1.932,0.868 1.067,0 0,0 m 2.766,3.081 0,1.618 -1.62,0 L 0,5.846 -1.145,4.699 l -1.62,0 0,-1.618 -1.145,-1.146 1.145,-1.147 0,-1.619 1.62,0 1.145,-1.146 1.146,1.146 1.62,0 0,1.62 1.144,1.146 -1.144,1.146 z"
-             inkscape:connector-curvature="0"
-             id="path22"
-             style="fill:#ffffff;fill-opacity:1;fill-rule:nonzero;stroke:none" /></g></g></g></g></svg>