[chore] Fix flaky Prometheus port collision in otelconftelemetry tests

[mx-psi]

Description

Uses new port for internal telemetry on each test to avoid flakiness because of port collision.

Authorship

• I, a human, wrote this pull request description myself.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.07%. Comparing base (8d9d794) to head (d20f80f).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #15731   +/-   ##
=======================================
  Coverage   91.07%   91.07%           
=======================================
  Files         732      732           
  Lines       48511    48511           
=======================================
  Hits        44181    44181           
  Misses       3011     3011           
  Partials     1319     1319           

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