fix: skip empty patterns in match_regex_list to prevent IndexError

match_regex_list indexes item_matcher[-1] to check for '$' suffix.
An empty string pattern causes IndexError: string index out of range.

This is reachable from CeleryIntegration.exclude_beat_tasks when
user configures an empty string in the pattern list.

Guard with if not item_matcher: continue before the index check.

Fixes #6504

Author: mangodxd

sentry_sdk/utils.py

@@ -1736,6 +1736,9 @@ def match_regex_list(
         return False
 
     for item_matcher in regex_list:
+        if not item_matcher:
+            continue
+
         if not substring_matching and item_matcher[-1] != "$":
             item_matcher += "$"
 

tests/test_utils.py

@@ -556,6 +556,9 @@ def test_include_source_context_when_serializing_frame(include_source_context):
         ["some-string", ["some.*"], True],
         ["some-string", ["Some"], False],  # we do case sensitive matching
         ["some-string", [".*string$"], True],
+        ["some-string", [""], False],  # empty pattern should not match
+        ["some-string", ["", "some-string"], True],  # empty pattern skipped, second matches
+        ["some-string", ["", ""], False],  # all empty patterns, no match
     ],
 )
 def test_match_regex_list(item, regex_list, expected_result):