Remove gfm.css, import from matrix-react-sdk

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/vector/index.ts

@@ -31,7 +31,6 @@ import "setimmediate";
 // Require common CSS here; this will make webpack process it into bundle.css.
 // Our own CSS (which is themed) is imported via separate webpack entry points
 // in webpack.config.js
-require("gfm.css/gfm.css");
 require("katex/dist/katex.css");
 
 /**