ref(relay): Only update internal state when it changed

[Dav1dde]

Removes the is_internal update from the relay_from_id function, to move the check to the endpoint (where it already was anyways). All additional uses of relay_from_id don't seem to care about the internal state, except authentication. So that seems fine, also this behaviour does seem more consistent.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.

:white_check_mark: All tests successful. No failed tests found.

Files	Patch %	Lines
...rc/sentry/api/endpoints/relay/register_response.py	0.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #76594       +/-   ##
===========================================
+ Coverage   56.44%   78.17%   +21.72%     
===========================================
  Files        6891     6904       +13     
  Lines      306655   306920      +265     
  Branches    52826    52821        -5     
===========================================
+ Hits       173090   239921    +66831     
+ Misses     128972    60606    -68366     
- Partials     4593     6393     +1800     

[Dav1dde]

PR. does what it was supposed to do: