fix(sync-v2): Fix dependencies update for the first block

[msbrogli]

Motivation

During QA, a full node syncing from scratch got stuck with the following logs:

2023-12-20 22:26:29 [info     ] [hathor.p2p.sync_v2.agent] requesting blocks streaming    end_block=[4094036, "b'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x01[\\xf20\\x82a\\x08\\x14\\xb2\\x83\\xe8\\x82\\xfc\\x8d*\\xe0f Ri6\\xb0@OS'"] peer=5a3040d quantity=424075 start_block=[3669962, "b'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x11\\x00\\xd7\\x93o\\xd9Y\\x02\\x0e\\x85\\xec\\xa6y*\\x0b7:LD;\\xa2\\xc2V\\x04'"]
2023-12-20 22:26:29 [info     ] [hathor.p2p.sync_v2.agent] requesting transactions streaming first_block=0000000000000062a0a3c362758d468f37692a14f1cf5cf2df2e08d5c92eab5a last_block=00000000000000005ea2ade4fdc528cd7ce5bb64bf942350e28c46aa8f79cf47 peer=5a3040d start_from=[]
2023-12-20 22:26:29 [info     ] [hathor.p2p.sync_v2.transaction_streaming_client] unexpected vertex received     peer=5a3040d tx_id=00000742224ab9e7084908b61a43ccbd9f0125b6e075e04d7f2355e8a67b1a06
2023-12-20 22:26:29 [info     ] [hathor.p2p.sync_v2.agent] tx streaming failed            peer=5a3040d reason=UnexpectedVertex('00000742224ab9e7084908b61a43ccbd9f0125b6e075e04d7f2355e8a67b1a06')

It got stuck because it was not adding dependencies it already had to the _existing_deps, so it was closing the streaming after receiving an unexpected vertex. In this case, the block has a direct dependency of the transaction 00000742224ab9e7084908b61a43ccbd9f0125b6e075e04d7f2355e8a67b1a06.

Acceptance Criteria

1. Call TransactionStreamingClient._update_dependencies() instead of running an old-and-buggy duplicated code.
2. Rename TransactionStreamingClient.update_dependencies() to _update_dependencies().

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[codecov]

Codecov Report

Attention: 23 lines in your changes are missing coverage. Please review.

Comparison is base (27381c1) 85.35% compared to head (8261720) 85.39%.
Report is 3 commits behind head on master.

Files	Patch %	Lines
hathor/reactor/reactor.py	63.33%	8 Missing and 3 partials ⚠️
hathor/debug_resources.py	70.00%	3 Missing ⚠️
hathor/stratum/stratum.py	57.14%	2 Missing and 1 partial ⚠️
hathor/p2p/sync_v2/transaction_streaming_client.py	60.00%	2 Missing ⚠️
hathor/websocket/factory.py	71.42%	2 Missing ⚠️
hathor/builder/cli_builder.py	66.66%	1 Missing ⚠️
hathor/wallet/resources/thin_wallet/send_tokens.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #897      +/-   ##
==========================================
+ Coverage   85.35%   85.39%   +0.03%     
==========================================
  Files         282      283       +1     
  Lines       22280    22305      +25     
  Branches     3366     3363       -3     
==========================================
+ Hits        19018    19048      +30     
+ Misses       2592     2588       -4     
+ Partials      670      669       -1     

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