test_coverage: fix formatting of --ignore-filename-regex

`black` suggests putting the string between single quotes so
there is no need to escape double quotes.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

integration_tests/test_coverage.py

@@ -82,7 +82,7 @@ def _get_current_coverage(coverage_config, no_cleanup, test_scope):
 
     additional_exclude_path = coverage_config["exclude_path"]
     if additional_exclude_path:
-        llvm_cov_command += f" --ignore-filename-regex \"{additional_exclude_path}\""
+        llvm_cov_command += f' --ignore-filename-regex "{additional_exclude_path}"'
 
     if test_scope == pytest.workspace:
         llvm_cov_command += " --workspace "