List amqp10 connections

[MarcialRosales]

Proposed Changes

This PR fixes issue #4238.

The issue was due to how we searched for the reader process along the supervisor hierarchy tree.
Additionally, we added the missing internal_info method that provided the info item pid which was missing from the reader module.

Types of Changes

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Put an x in the boxes that apply

• Bug fix (non-breaking change which fixes issue #NNNN)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• Documentation improvements (corrections, new content, etc)
• Cosmetic change (whitespace, formatting, etc)
• Build system and/or CI

[lukebakken]

@MarcialRosales thank you for this! I just have one question.

[lukebakken]

Testing results look good...

• Command output is as expected ✔️

  $ ./sbin/rabbitmqctl list_amqp10_connections
  Listing AMQP 1.0 connections ...
  pid
  <[email protected]>
  

• Viewing the connection from the management UI works as expected ✔️
• Closing the connection from the management UI works as expected ✔️

[ansd]

This PR introduces 2 new bugs:

1. It not only lists AMQP 1.0 connections, but also queries AMQP 0.9.1 connections.
2. Crashes occur when there are AMQP 0.9.1 connections.

To reproduce, run make -C deps/rabbitmq_amqp1_0 ct-command t=non_parallel_tests:when_one_connection FULL=1 with #9290 enabled, or manually create 1 AMQP 0.9.1 connection and run rabbitmqctl list_amqp10_connections and check the RabbitMQ log file:

crasher:
  initial call: rabbit_reader:init/3
  pid: <0.652.0>
  registered_name: []
  exception exit: {unexpected_message,{info,[pid],<0.707.0>}}
    in function  rabbit_reader:handle_other/2 (rabbit_reader.erl, line 640)
    in call from rabbit_reader:mainloop/4 (rabbit_reader.erl, line 531)
    in call from rabbit_reader:run/1 (rabbit_reader.erl, line 453)
    in call from rabbit_reader:start_connection/5 (rabbit_reader.erl, line 352)