adjust degradeRule sampleCount and support configurable (#2191)

[xiaomiusa87]

Describe what this PR does / why we need it

调整降级规则的时间窗口，支持可配置

Does this pull request fix one issue?

Fixes #2191

Describe how you did it

将降级规则的时间窗口从1 调整为SampleCountProperty.SAMPLE_COUNT

Describe how to verify it

Special notes for reviews

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