Update JmxMetric smoke test to use new assertion framework

[Copilot]

This PR updates the JmxMetric smoke test to use the new assertion framework introduced in #4141, making the test more readable and maintainable while keeping changes minimal.

Changes Made

1. Updated verifyJmxMetricsSentToBreeze method

• Replaced manual waitForItems calls with fluent testing.waitAndAssertMetric() calls
• Added individual metric assertions using the new framework for:
  • NameWithDot - validates value equals 5
  • DefaultJmxMetricNameOverride - validates metric exists
  • BooleanJmxMetric - validates value equals 1.0
  • DotInAttributeNameAsPathSeparator - validates metric exists
  • Loaded Class Count - validates metric exists

2. Extended MetricAssert class

• Added hasNoInternalAttributes() method to validate that metrics don't contain properties starting with applicationinsights.internal.
• This replaces the previous verifyNoInternalAttributes() helper method

3. Maintained existing logic

• Preserved the complex GC metrics and wildcard metric validation logic that requires collecting values to verify the wildcard sum
• Kept all existing edge case handling for different Java versions (Java 21+ behavior)

Testing

• ✅ JmxMetric smoke test passes with all 5 test variants (Java 8, 11, 17, 21, 23)
• ✅ Code formatting applied with spotlessApply
• ✅ Framework tests pass

The changes maintain backward compatibility while modernizing the assertions to use the new fluent API pattern.

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