remove unused terminal activity icon

src/vs/workbench/parts/terminal/electron-browser/media/terminal.css

@@ -3,13 +3,6 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-/* Activity Bar */
-.monaco-workbench > .activitybar .monaco-action-bar .action-label.terminal {
-	background: url('terminal.svg') center center no-repeat;
-	background-position: 50% !important;
-	background-size: 32px;
-}
-
 .monaco-workbench .panel.integrated-terminal {
 	align-content: flex-start;
 	align-items: baseline;

src/vs/workbench/parts/terminal/electron-browser/media/terminal.svg

-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32"><style>.icon-canvas-transparent{opacity:0;fill:#f6f6f6}.icon-white{fill:#ffffff}</style><path class="icon-canvas-transparent" d="M32 32H0V0h32v32z" id="canvas"/><g id="iconBg"><path class="icon-white" d="M16 2C8.28 2 2 8.28 2 16s6.28 14 14 14 14-6.28 14-14S23.72 2 16 2zm0 25.979C9.383 27.979 4 22.605 4 16 4 9.395 9.383 4.021 16 4.021S28 9.395 28 16c0 6.605-5.383 11.979-12 11.979zm-1.302-9.584l-1.069-1.105 1.429-1.394-1.437-1.435 1.08-1.104 2.541 2.538-2.544 2.5zM10 11.02v10h12v-10H10zm11 9H11v-8h10v8z"/></g></svg>
\ No newline at end of file