Re-enable Network Request Initiator view

[huntie]

Summary

Re-enables the Request Initiator UI subpanel, when the ENABLE_NETWORK_PANEL experiment is set (i.e. not the default configuration, currently used by Expo).

Test plan

✅ Tested locally

• 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 following the contribution guide for Meta employees OR contribution guide.
• This commit is React Native-specific and cannot be upstreamed.

[motiz88]

@huntie Are you looking to ship this now or only after we ship the backend functionality?

[huntie]

@motiz88 We can ship now, the panel is:

• Disabled without our backend support enabled, and when enabled — graceful empty state.
• Enabled with a preserved previous configuration for Expo — status quo.