Fix pylint 4.0.4

[rads-1996]

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• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
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[Copilot]

Pull request overview

This PR updates the azure-monitor-opentelemetry-exporter package (primarily tests, plus one runtime module) to accommodate new/changed Pylint findings in 4.0.4, mostly by removing unused imports and adding targeted # pylint: disable=... pragmas where needed.

Changes:

• Adds/adjusts Pylint suppression pragmas for specific warnings (e.g., broad-exception-caught, unused-argument, line-too-long, do-not-use-logging-exception, no-name-in-module).
• Cleans up unused imports and tweaks a couple of test names/strings to avoid Pylint complaints.
• Minor formatting change to a logged message string (removing implicit string concatenation).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/trace/test_trace_utils.py	Adds targeted Pylint suppression for fixedint import.
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/test_utils.py	Removes unused imports and renames one test for clearer intent.
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/test_storage.py	Removes a redundant local import and suppresses a line-length warning on a long comment line.
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/test_rate_limiter.py	Suppresses broad-exception-caught for a thread-safety test and removes an unused local import.
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/test_gen_ai_processor.py	Removes unused constant imports.
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/test_base_exporter.py	Removes an unused import in a test block.
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/quickpulse/test_exporter.py	Removes an unused client import and adds targeted suppressions for argument/line-length warnings.
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/performance_counters/test_performance_counters.py	Rewrites a string literal to avoid implicit concatenation.
sdk/monitor/azure-monitor-opentelemetry-exporter/tests/customer_sdk_stats/test_manager.py	Suppresses unused-argument for patched test parameters.
sdk/monitor/azure-monitor-opentelemetry-exporter/azure/monitor/opentelemetry/exporter/_performance_counters/_manager.py	Suppresses do-not-use-logging-exception at a module-init logging site.