[e2e] Wait for 'Session Storage' menu item to have children
[e2e] Wait for 'Session Storage' menu item to have children

Bug: chromium:1178496
Change-Id: Ifec32372a95172a3c1278d5e49e571ea69950538
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2790863
Reviewed-by: Philip Pfaffe <639a645feae3653b7aaefa0387217d375f2f82ff@chromium.org>
Commit-Queue: Simon Zünd <38944668e9e2ca98ccd0275b53370f90fa55c113@chromium.org>

ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend