fix: use T1 for sending chunk endorsements

[pugachAG]

We missed that when refactoring chunk endorsement logic. The old ChunkEndorsement message was removed in #12131, but we forgot to add the new message introduced in #11091.
I've noticed that by looking at mainnet metrics where VersionedChunkEndorsement message is only sent via T2.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.45%. Comparing base (164dc48) to head (db42601).
Report is 1 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #12632       +/-   ##
===========================================
+ Coverage    1.67%   70.45%   +68.78%     
===========================================
  Files         669      845      +176     
  Lines      119598   172287    +52689     
  Branches   119598   172287    +52689     
===========================================
+ Hits         2000   121390   +119390     
+ Misses     117495    45787    -71708     
- Partials      103     5110     +5007     

Flag	Coverage Δ
backward-compatibility	0.16% <ø> (?)
db-migration	0.16% <ø> (ø)
genesis-check	1.36% <ø> (ø)
linux	69.34% <ø> (+67.66%)	⬆️
linux-nightly	70.06% <ø> (?)
pytests	1.67% <ø> (ø)
sanity-checks	1.48% <ø> (ø)
unittests	70.28% <ø> (?)
upgradability	0.20% <ø> (ø)

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[saketh-are]

I think we should remove the catch-all _ => self == tcp::Tier::T2 and explicitly define the tier logic for every message type. It would prevent such problems in the future.

[pugachAG]

@saketh-are great idea! see #12634