Remove unused global statements flagged by flake8 F824

The global keyword is only needed for assignment, not reads.
These two declarations in test_cbwc005 only read the module-level
vars, so the global statements were unnecessary.

Author: T4rk1n

tests/integration/callbacks/test_wildcards.py

@@ -375,9 +375,6 @@ def update_output_on_page_pattern(value):
 
 
 def test_cbwc005_callbacks_count(dash_duo):
-    global fibonacci_count
-    global fibonacci_sum_count
-
     app = fibonacci_app(False)
     dash_duo.start_server(app)