Remove deprecated --slow-spec-threshold flag

Signed-off-by: Dale Haiducek <19750917+dhaiducek@users.noreply.github.com>
(cherry picked from commit f42f850)

Makefile

@@ -205,7 +205,7 @@ install-resources:
 
 .PHONY: e2e-test
 e2e-test: e2e-dependencies
-	$(GINKGO) -v --fail-fast --slow-spec-threshold=10s $(E2E_TEST_ARGS) test/e2e
+	$(GINKGO) -v --fail-fast $(E2E_TEST_ARGS) test/e2e
 
 .PHONY: e2e-test-coverage
 e2e-test-coverage: E2E_TEST_ARGS = --json-report=report_e2e.json --label-filter='!hosted-mode && !running-in-cluster' --output-dir=.