[improve][client] Remove JsonIgnore on ProducerConfigurationData.encryptionKeys

[cbornet]

Fixes #7579

Motivation

encryptionKeys is public data (the name of the keys to use, not the keys themselves) so there's no reason to hide it.
And it's a Set<String> so it serializes/deserializes fine with Jackson.

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• Anything that affects deployment

Documentation

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

Matching PR in forked repository

PR in forked repository: cbornet#8

[codecov-commenter]

Codecov Report

Merging #18351 (f9802e3) into master (a2c1534) will decrease coverage by 3.41%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master   #18351      +/-   ##
============================================
- Coverage     51.47%   48.06%   -3.42%     
- Complexity     7410     9387    +1977     
============================================
  Files           405      613     +208     
  Lines         44012    58392   +14380     
  Branches       4517     6088    +1571     
============================================
+ Hits          22656    28065    +5409     
- Misses        18935    27305    +8370     
- Partials       2421     3022     +601     

Flag	Coverage Δ
unittests	48.06% <ø> (-3.42%)	⬇️

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

Impacted Files	Coverage Δ
...ar/client/impl/conf/ProducerConfigurationData.java	84.70% <ø> (ø)
...oker/service/schema/SchemaRegistryServiceImpl.java	59.45% <0.00%> (-4.21%)	⬇️
...ava/org/apache/pulsar/broker/service/Consumer.java	69.68% <0.00%> (-2.13%)	⬇️
...ervice/AbstractDispatcherSingleActiveConsumer.java	69.15% <0.00%> (-1.87%)	⬇️
...apache/pulsar/proxy/server/LookupProxyHandler.java	56.46% <0.00%> (-1.73%)	⬇️
...he/pulsar/broker/admin/v2/NonPersistentTopics.java	60.64% <0.00%> (-1.39%)	⬇️
...a/org/apache/pulsar/client/impl/RawReaderImpl.java	83.90% <0.00%> (-1.15%)	⬇️
...rg/apache/pulsar/broker/web/PulsarWebResource.java	57.20% <0.00%> (-1.09%)	⬇️
...ice/persistent/PersistentMessageExpiryMonitor.java	43.75% <0.00%> (-1.05%)	⬇️
...tent/PersistentDispatcherSingleActiveConsumer.java	55.17% <0.00%> (-0.95%)	⬇️
... and 230 more