[sebxt]

Brokers report broker logger config entries with DYNAMIC_BROKER_LOGGER_CONFIG (6), and newer brokers use CLIENT_METRICS_CONFIG (7) and GROUP_CONFIG (8) for client metrics and group configs. ConfigSource stopped at SourceDefault (5), so describing a BrokerLoggerResource returned entries whose source printed as Source Invalid: 6 and could not be compared against a named constant.

This adds SourceDynamicBrokerLogger, SourceClientMetrics and SourceGroup with the ids used by the Java client's DescribeConfigsResponse.ConfigSource, and the matching String() cases. Wire encoding is unchanged; the decoder already stored the raw value.

TestDescribeConfigsResponseBrokerLoggerv1 decodes a v1 response for a broker logger resource with source 6 and checks the source name. TestConfigSourceString covers every source id. Both fail on main and pass with this change. go test ./... passes.

Fixes #3841