Tweak wording for Network dogfooding banner

[huntie]

Summary

Small tweak to improve first run experience (previous copy shown).

Test plan

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• This change maintains backwards compatibility with previous Local Storage data (if modifying settings, experiments, or other persisted client state).

Upstreaming plan

• This commit should be sent as a patch to the upstream devtools-frontend repo. I've reviewed the contribution guide.
• This commit is React Native-specific and cannot be upstreamed.