fix(plugins): wait for the network before the plugin update pass

[datlechin]

Why

#3507 deleted the NWPathMonitor without the fetch the plan put in its place (step 22). Offline at launch, the plugin update pass gave up after five tries, and reconnecting did not start it again.

Change

• The pass fetches the manifest on its own session with waitsForConnectivity and a 7-day resource timeout, so offline it waits for the network instead of spending tries.
• Interactive fetches keep the 30 s session, never join the pass's fetch, and return their own result.
• A connection waits for the pass only while it installs rejected plugins, not while it waits for the network.
• The 30 s, 5 min, 10 min retries stay, for a manifest that has no newer build yet.

Verified

connectionSkipsThePassWaitingForTheNetwork() fails when the pass joins the interactive fetch or holds connections during its fetch. RegistryClientFreshnessTests changed because fetch(policy:) now returns the manifest.