"jf docker scan" panic fix

[dortam888]

• All tests passed. If this feature is not already covered by the tests, I added new tests.
• All static analysis checks passed.
• This pull request is on the dev branch.
• I used gofmt for formatting the code before submitting the pull request.

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Fix an issue with jf dockerscan that had panic at usage.
Additionally, Fixed a typo in the usage that show jf jf docker scan instead of jf docker scan