Switch to ESM compatible build of trix

The mirror setup isn't doing what we need to get a ESM-compatible version of Trix. So grab a build from Snowpack that's compatible for now.

actiontext/app/javascript/trix/mirror.js

@@ -1 +0,0 @@
-import "trix"

actiontext/rollup.config.js

@@ -1,28 +1,14 @@
 import resolve from "@rollup/plugin-node-resolve"
 import commonjs from "@rollup/plugin-commonjs"
 
-export default [  
-  {
-    input: "app/javascript/actiontext/index.js",
-    output: {
-      file: "app/assets/javascripts/actiontext.js",
-      format: "es"
-    },
-    plugins: [
-      resolve(),
-      commonjs()
-    ]
+export default {
+  input: "app/javascript/actiontext/index.js",
+  output: {
+    file: "app/assets/javascripts/actiontext.js",
+    format: "es"
   },
-
-  {
-    input: "app/javascript/trix/mirror.js",
-    output: {
-      file: "app/assets/javascripts/trix.js",
-      format: "es"
-    },
-    context: "this",
-    plugins: [
-      resolve()
-    ]
-  }
-]
+  plugins: [
+    resolve(),
+    commonjs()
+  ]
+}