Allow == when null checking

[takayamaki]

This PR change eslint config to allow == when null checking.
By this PR, we can null or undefined checking at the once.

https://eslint.org/docs/latest/rules/eqeqeq#allow-null

fusagiko@yuika22:~/src/mastodon$ node 
Welcome to Node.js v16.20.0.
Type ".help" for more information.
> null == null
true
> null == undefined
true
> null == 0
false
> null == ""
false
> null == false
false
> false == 0
true
> false == ""
true
>

Of course eslint can detect if it's not null checking.

fusagiko@yuika22:~/src/mastodon$ git diff 
diff --git a/app/javascript/mastodon/compare_id.js b/app/javascript/mastodon/compare_id.js
index d2bd74f44..fe6483944 100644
--- a/app/javascript/mastodon/compare_id.js
+++ b/app/javascript/mastodon/compare_id.js
@@ -1,5 +1,5 @@
 export default function compareId (id1, id2) {
-  if (id1 === id2) {
+  if (id1 == id2) {
     return 0;
   }
 
fusagiko@yuika22:~/src/mastodon$ yarn test:lint:js
yarn run v1.22.19
$ eslint --ext=.js,.jsx,.ts,.tsx . --cache --report-unused-disable-directives

/home/fusagiko/src/mastodon/app/javascript/mastodon/compare_id.js
  2:11  error  Expected '===' and instead saw '=='  eqeqeq

/home/fusagiko/src/mastodon/app/javascript/mastodon/components/status.jsx
  523:13  warning  Avoid non-native interactive elements. If using native HTML is not possible, add an appropriate role and support for tabbing, mouse, keyboard, and touch inputs to an interactive content element  jsx-a11y/no-static-element-interactions

✖ 2 problems (1 error, 1 warning)

error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
fusagiko@yuika22:~/src/mastodon$