nbss: add parser tests

[jufajardini]

Add tests to parse_nbss_record and parse_nbss_record_partial

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• I have updated the user guide (in doc/userguide/) to reflect the changes made (if applicable)

Link to redmine ticket:

• There isn't one

Link to previous PR:

• nbss: add parser tests #5690

Describe changes:

• Add another test scenario where the packet doesn't have 'SMB'
• Insert space after '//'
• Fix typos

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[victorjulien]

Merged in #5693, thanks!