misc: drop babel.config.js file

This leaves jest testing non-functional, but having a babel.config.js interferes
with React Native.

Fixes: https://github.com/jitsi/jitsi-meet/issues/7450

babel.config.js

@@ -1,29 +0,0 @@
-// babel is used for jest
-// FIXME make jest work with webpack if possible?
-module.exports = {
-    env: {
-        test: {
-            plugins: [
-
-                // Stage 2
-                '@babel/plugin-proposal-export-default-from',
-                '@babel/plugin-proposal-export-namespace-from',
-                '@babel/plugin-proposal-nullish-coalescing-operator',
-                '@babel/plugin-proposal-optional-chaining',
-
-                // Stage 3
-                '@babel/plugin-syntax-dynamic-import',
-                [ '@babel/plugin-proposal-class-properties', { loose: false } ],
-                '@babel/plugin-proposal-json-strings',
-
-                // lib-jitsi-meet
-                '@babel/plugin-transform-flow-strip-types'
-            ],
-            presets: [
-                '@babel/env',
-                '@babel/preset-flow',
-                '@babel/react'
-            ]
-        }
-    }
-};