[soujasK]

Issue number: closes #8667

Summary

Changes

POWERTOOLS_METRICS_DISABLED (added in #6046 for both providers) was only checked in flush_metrics(). This adds the same is_metrics_disabled() check to the other emission paths:

• single_metric (metrics/base.py): only prints when metrics aren't disabled. This also covers the CloudWatch ColdStart metric, which is emitted through single_metric. It also no longer prints a null line when the with body raises (metric_set is still None at that point); the exception still propagates.
• AmazonCloudWatchEMFProvider.add_metric: the automatic flush at 100 metrics / 100 values doesn't print when disabled. The metric set is still cleared, as before.
• DatadogProvider.flush_metrics: doesn't submit through datadog_lambda's lambda_metric when disabled.

Since is_metrics_disabled() also returns true for POWERTOOLS_DEV=true without POWERTOOLS_METRICS_DISABLED, single_metric and the cold start metric are now silent in dev mode too, the same as flush_metrics() already was.

The legacy MetricManager in metrics/base.py isn't changed: it's only reached through SingleMetric, which can't hit its auto-flush.

Tests: one per path (single_metric, cold start via log_metrics, the 100-metric auto-flush, Datadog lambda_metric mocked), a POWERTOOLS_DEV case for single_metric, and the null line when the body raises. The five path tests fail without the change. tests/functional/metrics passes; on Linux (Python 3.12) ruff, mypy, ty, bandit and xenon pass. Running tests/unit, tests/functional/metrics and tests/functional/batch together on Linux, test_datadog_write_to_log_with_env_variable fails the same way on develop without this change (it passes on its own), so it looks like existing cross-test state.

User experience

Before: with metrics disabled, the ColdStart metric, single_metric, the 100-metric auto-flush and Datadog extension submissions were still emitted (and EMF lines are ingested by CloudWatch).

After: nothing is emitted when metrics are disabled.

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[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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