fix: VulnerabilityFinding equality should exclude other record types

What does this MR do?

fix: vulnerability_findings equality should exclude other record types

Our previous comparison between finding records did not properly check the class type to ensure non-finding records are properly excluded. This can occur when multiple records are created within a transaction (such as Vulnerabilities::CreateService and a simple Array#uniq check is performed.

• #332825 (closed)
• #332539 (closed)
• #332538 (closed)

Does this MR meet the acceptance criteria?

Conformity

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Security

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• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
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