Add `assume_valid_target_reached: bool` to `NetRpc::sync_state`

[eval-exec]

What problem does this PR solve?

Issue Number: close #4485

What's Changed:

Related changes

• Add assume_valid_target_reached: bool and min_chain_work_reached: bool to sync_state RPC
• let check_assume_valid_target don't reset SyncConfig::assume_valid_target to None if the assume target has found in Snapshot.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code ci-runs-only: [ quick_checks,linters ]

Side effects

• Performance regression
• Breaking backward compatibility

Release note

Title Only: Include only the PR title in the release note.

[quake]

could you please add min_chain_work field also?

[eval-exec]

I think this PR is ready for review.