Switch editor to full MathJax package to fix broken autoloads

Re: https://forums.ankiweb.net/t/anki-2-1-53-release-candidate/20122/2

Autoloads in MathJax are asynchronous, and the caller is expected to
use asynchronous APIs when they are in use [1]. The editor uses the synchronous
tex2svg(), which throws a "MathJax retry" error when an autoload package
has not yet loaded. Attempting to use the package before it has loaded
appears to break future invocations as well, so the package fails to work
at all until a new webview is created.

The following HTML will reproduce the issue when added to a single card
in a new profile:

```
<strong>6&nbsp; &nbsp;&nbsp;</strong>Every combination of <anki-mathjax>\boldsymbol{v}=(1,-2,1)</anki-mathjax> and <anki-mathjax>\boldsymbol{w}=(0,1,-1)</anki-mathjax> has components that add to&nbsp; _____.<br>
```

Ideally we'd switch the MathJax rendering to be asynchronous, but that
didn't work well when I tried it in #1862. For now I've just switched
to the full package, which adds about 130KB to the final minified JS
(2.76MB), and likely slows down editor loading somewhat.

[1] https://github.com/mathjax/MathJax/issues/2557#issuecomment-727655089

ts/editable/mathjax.ts

@@ -5,7 +5,7 @@
 @typescript-eslint/no-explicit-any: "off",
  */
 
-import "mathjax/es5/tex-svg";
+import "mathjax/es5/tex-svg-full";
 
 import { mathIcon } from "./icons";