feat: sbom verifier improvements

[susanshi]

Description

• adding a e2e test for SBOM verifier
• update error handling logic to return err in a verifier report, returning the err in the report is a better user experience.
• updated license check to match on whole word

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):

Fixes #

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Helm Chart Change (any edit/addition/update that is necessary for changes merged to the main branch)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also list any relevant details for your test configuration

• Test A
• Test B

Checklist:

• Does the affected code have corresponding tests?
• Are the changes documented, not just with inline documentation, but also with conceptual documentation such as an overview of a new feature, or task-based documentation like a tutorial? Consider if this change should be announced on your project blog.
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have appropriate license header?

Post Merge Requirements

• MAINTAINERS: manually trigger the "Publish Package" workflow after merging any PR that indicates Helm Chart Change

[codecov]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (f44d451) 55.13% compared to head (b4048f0) 55.13%.

Files	Patch %	Lines
plugins/verifier/sbom/sbom.go	63.63%	4 Missing ⚠️
plugins/verifier/sbom/utils/spdxutils.go	80.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1205   +/-   ##
=======================================
  Coverage   55.13%   55.13%           
=======================================
  Files         104      104           
  Lines        6865     6879   +14     
=======================================
+ Hits         3785     3793    +8     
- Misses       2749     2753    +4     
- Partials      331      333    +2     

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[akashsinghal]

LGTM