[jsinterp] Improve separating regex

Fixes https://github.com/yt-dlp/yt-dlp/issues/4635#issuecomment-1273974909

test/test_jsinterp.py

@@ -392,6 +392,11 @@ class TestJSInterpreter(unittest.TestCase):
         ''')
         self.assertEqual(jsi.call_function('x').pattern, r',][}",],()}(\[)')
 
+        jsi = JSInterpreter(R'''
+        function x() { let a=[/[)\\]/]; return a[0]; }
+        ''')
+        self.assertEqual(jsi.call_function('x').pattern, r'[)\\]')
+
     def test_char_code_at(self):
         jsi = JSInterpreter('function x(i){return "test".charCodeAt(i)}')
         self.assertEqual(jsi.call_function('x', 0), 116)

test/test_youtube_signature.py

@@ -130,6 +130,10 @@ _NSIG_TESTS = [
         'https://www.youtube.com/s/player/5a3b6271/player_ias.vflset/en_US/base.js',
         'B2j7f_UPT4rfje85Lu_e', 'm5DmNymaGQ5RdQ',
     ),
+    (
+        'https://www.youtube.com/s/player/7a062b77/player_ias.vflset/en_US/base.js',
+        'NRcE3y3mVtm_cV-W', 'VbsCYUATvqlt5w',
+    ),
 ]