Repair metric tag config metadata type conflicts

[riyazsh]

Summary

• add an explicit opt-in sync/migrate flag to repair metric tag configuration metadata type conflicts
• when enabled, a create/update that fails because destination metrics metadata has a different type sets destination metadata to the source tag configuration metric_type, then retries once
• keep the default behavior unchanged: metadata type conflicts still propagate unless the repair flag is set

Safety

This mutates destination metrics metadata, so the flag is intentionally off by default. Operators should enable it only after confirming the source tag configuration type is the desired source of truth.

Tests

• pytest -q tests/unit/test_metric_tag_configurations.py tests/unit/test_metric_tag_config_metadata_type_repair_cli.py tests/unit/test_metrics_metadata.py
• pytest -q tests/unit -k 'not custom_client_trust_env and not id_file_subprocess_experiment'
• python -m ruff check --select F,E9 datadog_sync/model/metric_tag_configurations.py datadog_sync/utils/configuration.py datadog_sync/commands/shared/options.py tests/unit/test_metric_tag_configurations.py tests/unit/test_metric_tag_config_metadata_type_repair_cli.py