Fix invalid syntax in log analyzer (sonic-net#11558)

What is the motivation for this PR?
when running testcase with log analyzer, would get error:
E File "/data/sonic-mgmt-int/tests/common/plugins/loganalyzer/loganalyzer.py", line 167
E file_path = os.path.join(tmp_folder, f"log_error_{self.marker_prefix}_{cur_time}.json")
E ^
E SyntaxError: invalid syntax

How did you do it?
use .format() instead of f""

tests/common/plugins/loganalyzer/loganalyzer.py

@@ -164,7 +164,7 @@ def save_matching_errors(self, result_log_errors):
             tmp_folder = "/tmp/loganalyzer/{}".format(self.ansible_host.hostname)
             os.makedirs(tmp_folder, exist_ok=True)
             cur_time = time.strftime("%d_%m_%Y_%H_%M_%S", time.gmtime())
-            file_path = os.path.join(tmp_folder, f"log_error_{self.marker_prefix}_{cur_time}.json")
+            file_path = os.path.join(tmp_folder, "log_error_{}_{}.json".format(self.marker_prefix, cur_time))
             logging.info("Log errors will be saved in file: {}".format(file_path))
             data = {'log_errors': log_errors}
             with open(file_path, "w+") as file: