chore: few more improvements for the academy exercises (#2268)

- removes leftover file spotted by @TC-MO 
- removes workaround as
apify/crawlee-python#1673 has been fixed
meanwhile by the Crawlee team
- adds tests which verify that each exercise has its test :)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Test-only changes plus deletion of an unused exercise script; minimal
production impact, with only a small risk of CI failures if tests are
missing or external scraping outputs change.
> 
> **Overview**
> Improves the academy webscraping exercise test suites by adding a new
"covers all exercise scripts" check in both JS (`*.mjs`) and Python
(`*.py`) that fails when any exercise file lacks a corresponding test
invocation.
> 
> Removes the leftover `wikipedia_calling_codes.mjs` exercise file, and
updates the Python Crawlee Netflix ratings test to assert an exact
dataset size (`-eq 5`) instead of the prior workaround.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
f68b908. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: honzajavorek

sources/academy/webscraping/scraping_basics_javascript/exercises/test.bats

@@ -12,6 +12,19 @@ teardown_file() {
   rm -rf node_modules package.json package-lock.json
 }
 
+@test "covers all exercise scripts" {
+  local missing
+  missing=0
+
+  for file in *.mjs; do
+    if ! grep -q "node $file" test.bats; then
+      echo "Missing test for $file"
+      missing=1
+    fi
+  done
+
+  [[ $missing -eq 0 ]]
+}
 
 @test "outputs the HTML with Star Wars products" {
   run node lego.mjs

sources/academy/webscraping/scraping_basics_javascript/exercises/wikipedia_calling_codes.mjs

@@ -6,6 +6,20 @@ teardown() {
   rm -rf products.json storage dataset.json
 }
 
+@test "covers all exercise scripts" {
+  local missing
+  missing=0
+
+  for file in *.py; do
+    if ! grep -q "python $file" test.bats; then
+      echo "Missing test for $file"
+      missing=1
+    fi
+  done
+
+  [[ $missing -eq 0 ]]
+}
+
 @test "outputs the HTML with Star Wars products" {
   run uv run -q --with=httpx python lego.py
 
@@ -141,7 +155,7 @@ teardown() {
 
   (( status == 0 ))
   [[ -f dataset.json ]]
-  [[ $(cat dataset.json | jq '. | length') -gt 5 ]]  # should be -eq 5, but there is a bug https://github.com/apify/crawlee-python/issues/1673
+  [[ $(cat dataset.json | jq '. | length') -eq 5 ]]
   [[ $(cat dataset.json | jq -c '.[0] | keys') == '["rating","title","url"]' ]]
   [[ $(cat dataset.json | jq '.[].url') == *"https://www.imdb.com/title/"* ]]
 }