[linter] Enable ESLint rule no-console (#3810)

In PR #3806 I noticed that ESLint did not complain about the use of
`console`. Then I realised that the rule `no-console` was not activated.
I have now changed this and replaced a few places where `console` was
used.

We can't apply the rule to all .js files because not all of them use our
logger. Therefore I had to add an extra config block for it.

eslint.config.mjs

@@ -84,6 +84,16 @@ export default defineConfig([
 			"sort-keys": "off"
 		}
 	},
+	{
+		files: ["**/*.js"],
+		ignores: [
+			"clientonly/index.js",
+			"modules/default/calendar/debug.js",
+			"js/logger.js",
+			"tests/**/*.js"
+		],
+		rules: {"no-console": "error"}
+	},
 	{
 		files: ["**/package.json"],
 		plugins: {packageJson},