Improve channel and port filter policy parsing

[ljoss17]

Closes: #4045

Description

This PR adds whitespace trimming before parsing values in the list of packet_filter configuration.

This will avoid triggering channel scanning if there is an unintended whitespace, e.g.:

    policy = "allow"
    list = [
        [ "transfer", "channel-1 ", ],
    ]

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PR author checklist:

• Added changelog entry, using unclog.
• Added tests: integration (for Hermes) or unit/mock tests (for modules).
• Linked to GitHub issue.
• Updated code comments and documentation (e.g., docs/).
• Tagged one reviewer who will be the one responsible for shepherding this PR.

Reviewer checklist:

• Reviewed Files changed in the GitHub PR explorer.
• Manually tested (in case integration/unit/mock tests are absent).