Chore: enable array-bracket-spacing on ESLint codebase (#7830)

There were about 900 existing violations with the `never` option, and about 20000 existing violations with the `always` option enabled, so I used the default `never` option.

The changes were all made using ESLint's autofixer.

Author: not-an-aardvark

index.js

@@ -59,7 +59,7 @@ function formatMessage(message, parentResult) {
         sourceCode ? `at ${filePath}:` : `at ${filePath}`,
     ].filter(String).join(" ");
 
-    const result = [ firstLine ];
+    const result = [firstLine];
 
     if (sourceCode) {
         result.push(