Tiny shovel-related fixes

[gomoripeti]

Proposed Changes

• Remove unused fields from shovel_worker state record

  These fields were moved to the config map with the introduction of protocol callbacks.

• Fix table layout for terminated shovel status

  I believe this is rarely visible as the shovel is quickly restarted or removed after termination.

• Fix error handling of shovel_management delete/restart shovel

  An rpc:call can return {badrcp, Reason} with an arbitrary Reason term,
  so it cannot be passed to rabbit_log:error/1 which expects an atom,
  string or binary as its argument.

  This fixes the below crash

 exception error: no function clause matching
                  logger:do_log_allowed(error,
                                        {{'EXIT',
                                          {{badmatch,
...
   in function  rabbit_shovel_mgmt:delete_resource/2 (rabbit_shovel_mgmt.erl, line 92)

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• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
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• Cosmetic change (whitespace, formatting, etc)
• Build system and/or CI

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Further Comments

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[michaelklishin]

There is a repeatable failure in the Shovel management plugin suite.

[michaelklishin]

Here is the exception from Common Test:

=== Ended at 2022-09-28 15:09:12
=== Location: [{rabbit_shovel_mgmt,delete_resource,82},
              {rabbit_shovel_mgmt_SUITE,delete_resource_badrpc,[87](file:///private/var/tmp/_bazel_antares/14f90f8a31f5e7ccfc4ded95d3ba96d8/execroot/__main__/bazel-out/darwin-fastbuild/testlogs/deps/rabbitmq_shovel_management/rabbit_shovel_mgmt_SUITE/test.outputs/outputs/ct_run.ct-rabbitmq_shovel_management-rabbit_shovel_mgmt_SUITE@klishinm-a02.2022-09-28_15.09.11/deps.rabbitmq_shovel_management.rabbit_shovel_mgmt_SUITE.logs/run.2022-09-28_15.09.11/rabbit_shovel_mgmt_suite.src.html#87)},
              {test_server,ts_tc,1782},
              {test_server,run_test_case_eval1,1291},
              {test_server,run_test_case_eval,1223}]
=== === Reason: no case clause matching {error,
                                          {corrupt_or_missing_cluster_files,
                                           {error,enoent},
                                           {error,enoent}}}
  in function  rabbit_shovel_mgmt:delete_resource/2 (rabbit_shovel_mgmt.erl, line 82)
  in call from rabbit_shovel_mgmt_SUITE:delete_resource_badrpc/1 (rabbit_shovel_mgmt_SUITE.erl, line 87)
  in call from test_server:ts_tc/3 (test_server.erl, line 1782)

[gomoripeti]

it's the very testcase that I added, that fails, a bit embarrassing. will find the time to fix next week