[js] add big data file to formatter ignore list (#21767)

### Description

Add the big data file `web/test/data/ops/pad-big.jsonc` to formatter
ignore list. This file slows down the formatter quite a lot at local.

js/.prettierignore

@@ -1,7 +1,10 @@
 # ignore generated docs
 web/docs/
 
-# this JSON file is too large, so it takes too long to format it.
+# these JSON file is too large, so it takes too long to format it.
+web/test/data/ops/pad-big.jsonc
+web/test/testdata-config.json
+web/test/ort.test.js
 node/test/testdata/squeezenet.input0.json
 
 # ignore dist folder