[fix][broker] Restore the broker id to match the format used in existing Pulsar releases

[lhotari]

Motivation

The "lookup service address" format was changed in PR #21015 based on an invalid issue report #21012.
"lookup service address" has been renamed to "brokerId" in #21894 to reduce confusion.
The value is not a service address to be used by any connections to the broker. It is used in the Pulsar load manager as
a unique runtime identifier for a broker instance.

It's better to not change the broker id format since there isn't a reason to do this. The format used in existing Pulsar releases should be restored and that's the motivation for this PR.

There was a misconception that PR #17136 would have changed the format in Pulsar 2.11 release. That PR didn't change the format. It can be verified from the diff.

Modifications

• restore the broker id format to match the format used in existing Pulsar releases
• fix tests that are using incorrect ways to find the broker id for a broker instance

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (5cb12a5) 73.76% compared to head (9fbef92) 73.59%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #21937      +/-   ##
============================================
- Coverage     73.76%   73.59%   -0.17%     
+ Complexity    32476    32411      -65     
============================================
  Files          1861     1861              
  Lines        138605   138677      +72     
  Branches      15186    15187       +1     
============================================
- Hits         102238   102066     -172     
- Misses        28505    28711     +206     
- Partials       7862     7900      +38     

Flag	Coverage Δ
inttests	24.09% <33.33%> (-0.11%)	⬇️
systests	23.67% <33.33%> (-0.08%)	⬇️
unittests	72.86% <83.33%> (-0.18%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...n/java/org/apache/pulsar/broker/PulsarService.java	82.29% <100.00%> (-1.77%)	⬇️
...ache/pulsar/client/admin/internal/BrokersImpl.java	87.50% <100.00%> (ø)
...g/apache/pulsar/broker/admin/impl/BrokersBase.java	70.86% <50.00%> (ø)

... and 87 files with indirect coverage changes