test: mark test-inspector-network-fetch as flaky again

https://redirect.github.com/nodejs/node/pull/59104 did not fix it
and it's still flaky in the CI.

Refs: https://github.com/nodejs/reliability/blob/main/reports/2025-08-26.md
Refs: #59090
PR-URL: #59640
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: joyeecheung

test/parallel/parallel.status

@@ -25,6 +25,8 @@ test-sqlite: PASS, FLAKY
 [$system==win32]
 # https://github.com/nodejs/node/issues/54807
 test-runner-watch-mode-complex: PASS, FLAKY
+# https://github.com/nodejs/node/issues/59090
+test-inspector-network-fetch: PASS, FLAKY
 # https://github.com/nodejs/node/issues/54808
 test-async-context-frame: PASS, FLAKY
 # https://github.com/nodejs/node/issues/59636