Set unique_id_from_tool from matrix field in Dependency Track parser

[samiat4911]

Description
The Dependency Track parser currently sets vuln_id_from_tool but never sets unique_id_from_tool. Users who configure the unique_id_from_tool_or_hash_code deduplication algorithm experience duplicate findings on reimport because the field is empty.

Approach: This PR maps the Dependency Track FPF finding's matrix field (a stable composite of project_uuid:component_uuid:vulnerability_uuid) to the unique_id_from_tool field on the Finding model. The default deduplication algorithm (hash_code) is unchanged, ensuring existing deployments are not negatively affected.

Impact: Enables accurate cross-scan deduplication for Dependency Track imports, improving data integrity and scalability for organisations managing large vulnerability datasets.

Test results

• Extended tests/unittests/tools/test_dependency_track_parser.py with unique_id_from_tool assertions across 4 existing test cases (test_has_one_finding, test_v3_8_0, test_findings_with_alias, test_findings_with_cvssV3_score).
• Validated that all existing fixture files contain the matrix field and pass the new assertions.
• Ruff linting passes cleanly across modified files.

Visual Evidence (Parser Changes):

# dojo/tools/dependency_track/parser.py 
# (Showing lines 230-236)
            component_version=component_version,
            file_path=file_path,
            vuln_id_from_tool=vuln_id_from_tool,
            unique_id_from_tool=dependency_track_finding.get("matrix"), # <- ADDED THIS LINE
            static_finding=True,
            dynamic_finding=False)

Visual Evidence (Test Changes):

# unittests/tools/test_dependency_track_parser.py
# (Showing lines 54-61)
            parser = DependencyTrackParser()
            findings = parser.get_findings(testfile, Test())
            self.assertEqual(1, len(findings))
            self.assertEqual( # <- ADDED THIS LINE AND BELOW
                "ca4f2da9-0fad-4a13-92d7-f627f3168a56:b815b581-fec1-4374-a871-68862a8f8d52:115b80bb-46c4-41d1-9f10-8a175d4abb46",
                findings[0].unique_id_from_tool,
            )

Checklist

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• Add applicable tests to the unit tests.
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