feat: recognize message.timestamp.after.max.ms and before.max.ms settings

[pratikmallya]

These Kafka 3.6+ topic configs bound how far a message timestamp can
diverge from broker time in either direction. topicctl's config
validator didn't have entries for them, so any topic YAML explicitly
setting these keys failed with "not recognized topic config setting"
even though brokers (including Confluent Cloud) support and return
them (see #191).

Add validators using the same non-negative int64 pattern as sibling
settings like delete.retention.ms.

upstream docs: https://docs.confluent.io/platform/current/installation/configuration/topic-configs.html#message-timestamp-after-max-ms and https://docs.confluent.io/platform/current/installation/configuration/topic-configs.html#message-timestamp-before-max-ms

Testing

built and run this locally. The error message changed from:

-----------------+----+------------------------------------------------------------------------------
       NAME      | OK |                                   DETAILS
-----------------+----+------------------------------------------------------------------------------
  config correct | ✗  | config validation error: 1 error occurred:
                 |    |         * Key message.timestamp.after.max.ms is not recognized topic config setting
                 |    |
                 |    |
-----------------+----+------------------------------------------------------------------------------

to

-----------------------------+----+--------------------------------------------------------------------------------------------------
             NAME            | OK |                                             DETAILS
-----------------------------+----+--------------------------------------------------------------------------------------------------
  config correct             | ✓  |
  configs consistent         | ✓  |
  topic exists               | ✓  |
  config settings correct    | ✗  | 1 keys have different values between cluster and topic config: [message.timestamp.after.max.ms]
  replication factor correct | ✓  |
  partition count correct    | ✓  |
  throttles clear            | ✓  |
  replicas in-sync           | ✓  |
-----------------------------+----+--------------------------------------------------------------------------------------------------

which is expected (this is before apply)

[pratikmallya]

@petedannemann @hhahn-tw not sure how notification works for this repo, the codeowners seem to point to a team that doesn't exist, just tagging y'all from the commit history, apologies if that isn't the right process.