Fix core_dump_and_config_check in conftest (sonic-net#13619)

What is the motivation for this PR?
Currently compare_running_config would return True if the first key / value is equal, which is incorrect.
Sample:
pre_running_config = {
"key_a": "value_a",
"key_b": "value_b"
}
cur_running_config = {
"key_a": "value_a",
"key_b": "another_value"
}
After compare "key_a" and find that they are equal, it will return True directly rather than continue to compare "key_b"

How did you do it?
Remove the incorrect return

How did you verify/test it?
Run tests

tests/conftest.py

@@ -2064,7 +2064,7 @@ def compare_running_config(pre_running_config, cur_running_config):
             for key in pre_running_config.keys():
                 if not compare_running_config(pre_running_config[key], cur_running_config[key]):
                     return False
-                return True
+            return True
         # We only have string in list in running config now, so we can ignore the order of the list.
         elif type(pre_running_config) is list:
             if set(pre_running_config) != set(cur_running_config):