crypto: Refer to MSC4362 when we are talking about encrypted state

[andybalaam]

MSC4362 is now a grown-up MSC all on its own, not based on MSC3414, and what we have implemented is for MSC4362, so rename everything to refer to that.

Related: ruma/ruma#2287

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.60%. Comparing base (9ab886f) to head (f5cdc6b).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5868   +/-   ##
=======================================
  Coverage   88.59%   88.60%           
=======================================
  Files         363      363           
  Lines      102888   102888           
  Branches   102888   102888           
=======================================
+ Hits        91153    91162    +9     
+ Misses       7496     7485   -11     
- Partials     4239     4241    +2     

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[codspeed-hq]

CodSpeed Performance Report

Merging #5868 will not alter performance

_{Comparing andybalaam/encrypted-state-events-is-msc4362 (f5cdc6b) with main (9ab886f)}

Summary

✅ 50 untouched