fix(report): hide empty tables if all vulns has been filtered

[DmitriyLewen]

Description

We added --show-suppressed flag to show suppressed vulns.
But when all vulnerabilities for language package was filtered out - we still show empty table.

before:

➜ trivy -q rootfs ./log4j-core-2.17.0.jar --ignorefile ./.trivyignore.yaml

Java (jar)

Total: 0 (UNKNOWN: 0, LOW: 0, MEDIUM: 0, HIGH: 0, CRITICAL: 0)

after:

➜ trivy -q rootfs ./log4j-core-2.17.0.jar --ignorefile ./.trivyignore.yaml

If --show-suppressed is used - we still show table (only target and Total: 0...):

➜  trivy -q rootfs ./log4j-core-2.17.0.jar --ignorefile ./.trivyignore.yaml --show-suppressed

Java (jar)

Total: 0 (UNKNOWN: 0, LOW: 0, MEDIUM: 0, HIGH: 0, CRITICAL: 0)


Suppressed Vulnerabilities (Total: 1)

┌─────────────────────────────────────┬────────────────┬──────────┬─────────┬───────────┬───────────────────┐
│               Library               │ Vulnerability  │ Severity │ Status  │ Statement │      Source       │
├─────────────────────────────────────┼────────────────┼──────────┼─────────┼───────────┼───────────────────┤
│ org.apache.logging.log4j:log4j-core │ CVE-2021-44832 │ MEDIUM   │ ignored │ N/A       │ .trivyignore.yaml │
└─────────────────────────────────────┴────────────────┴──────────┴─────────┴───────────┴───────────────────┘

Related issues

• Close Report is not empty even if there are no findings #6351

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).