feat(metrics): optimzie to support dynamic metrics config

[Rancho-7]

The e2e test results are shown as below

================================================================================
SESSION REPORT (ALL TESTS)
ducktape version: 0.11.4
session_id:       2026-01-08--009
run time:         5 minutes 38.223 seconds
tests run:        4
passed:           4
flaky:            0
failed:           0
ignored:          0
================================================================================
test_id:    kafkatest.tests.core.automq_telemetry_test.AutoMQBrokerTelemetryTest.test_dynamic_prometheus_exporter_reconfiguration
status:     PASS
run time:   1 minute 3.004 seconds
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test_id:    kafkatest.tests.core.automq_telemetry_test.AutoMQBrokerTelemetryTest.test_prometheus_metrics_exporter
status:     PASS
run time:   1 minute 6.223 seconds
--------------------------------------------------------------------------------
test_id:    kafkatest.tests.core.automq_telemetry_test.AutoMQBrokerTelemetryTest.test_s3_log_uploader
status:     PASS
run time:   1 minute 11.146 seconds
--------------------------------------------------------------------------------
test_id:    kafkatest.tests.core.automq_telemetry_test.AutoMQBrokerTelemetryTest.test_s3_metrics_exporter
status:     PASS
run time:   2 minutes 17.602 seconds
--------------------------------------------------------------------------------