refractor: Replace manual autosize of textarea with compose_ui autosize.

This commit make compose_ui.autosize_textarea handle most of the autosize
logic of the textarea. It audits for any logic that is trying to do
autosize manually and replace it with compose_ui.autosize_textarea.
This allows to have better check for when the textarea is autosized.

Mainly done this so that we can have a check on #compose-textarea when
to autosize and when not to, thus helping to have all the logic in only
one function.

static/js/compose_actions.js

@@ -467,7 +467,7 @@ export function quote_and_reply(opts) {
         const fence = fenced_code.get_unused_fence(message.raw_content);
         content += `${fence}quote\n${message.raw_content}\n${fence}`;
         compose_ui.replace_syntax("[Quoting…]", content, textarea);
-        autosize.update($("#compose-textarea"));
+        compose_ui.autosize_textarea($("#compose-textarea"));
     }
 
     if (message && message.raw_content) {

static/js/compose_ui.js

@@ -51,9 +51,7 @@ export function smart_insert(textarea, syntax) {
         textarea.caret(syntax);
     }
 
-    // This should just call exports.autosize_textarea, but it's a bit
-    // annoying for the unit tests, so we don't do that.
-    autosize.update(textarea);
+    autosize_textarea(textarea);
 }
 
 export function insert_syntax_and_focus(syntax, textarea = $("#compose-textarea")) {

static/js/composebox_typeahead.js

@@ -1,4 +1,3 @@
-import autosize from "autosize";
 import {formatISO} from "date-fns";
 import ConfirmDatePlugin from "flatpickr/dist/plugins/confirmDate/confirmDate";
 import $ from "jquery";
@@ -176,7 +175,7 @@ export function handle_enter(textarea, e) {
         // Now add the newline, remembering to resize the
         // textarea if needed.
         textarea.caret("\n");
-        autosize.update(textarea);
+        compose_ui.autosize_textarea(textarea);
         e.preventDefault();
         return;
     }