Remove useless icon

Signed-off-by: Mario Danic <mario@lovelyhq.com>

app/src/main/res/drawable/ic_voice_chat_black_24dp.xml

@@ -1,25 +0,0 @@
-<!--
-  ~ Nextcloud Talk application
-  ~
-  ~ @author Mario Danic
-  ~ Copyright (C) 2017 Mario Danic
-  ~
-  ~ This program is free software: you can redistribute it and/or modify
-  ~ it under the terms of the GNU General Public License as published by
-  ~ the Free Software Foundation, either version 3 of the License, or
-  ~ at your option) any later version.
-  ~
-  ~ This program is distributed in the hope that it will be useful,
-  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
-  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-  ~ GNU General Public License for more details.
-  ~
-  ~ You should have received a copy of the GNU General Public License
-  ~ along with this program.  If not, see <http://www.gnu.org/licenses/>.
-  -->
-
-<vector android:autoMirrored="true" android:height="24dp"
-    android:viewportHeight="24.0" android:viewportWidth="24.0"
-    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
-    <path android:fillColor="#FF000000" android:pathData="M20,2L4,2c-1.1,0 -1.99,0.9 -1.99,2L2,22l4,-4h14c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM18,14l-4,-3.2L14,14L6,14L6,6h8v3.2L18,6v8z"/>
-</vector>