bug: remove trivy DB to reduce 1.2 Gb space

[ganeshkumarashok]

What type of PR is this? /kind cleanup

What this PR does / why we need it: Remove trivy DB that is not being used post VHD-build and trivy security report generation.

Which issue(s) this PR fixes:

Fixes #

Requirements:

• [ ] uses conventional commit messages
• [ ] includes documentation
• [ ] adds unit tests
• [ ] tested upgrade from previous version

Special notes for your reviewer:

Release note:

none

[coveralls]

Pull Request Test Coverage Report for Build 6897257369

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 79.007%

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Totals
Change from base Build 6897090956:	0.0%
Covered Lines:	2243
Relevant Lines:	2839

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💛 - Coveralls