fix:Ensure security.txt file ends with a newline character

[Agnibaan]

• Resolves: security.txt should end with a newline #42611

Summary

This commit addresses issue #42611 by ensuring that the generated security.txt file consistently ends with a newline character. This change aligns the file with the recommended best practices outlined in RFC 9116.

Additionally, the commit updates the relevant unit test to verify that the newline character is correctly added.

TODO

• ...

before

after

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[Agnibaan]

@skjnldsv @Pytal Hey can u guys review this request....

[Agnibaan]

hey @joshtrichards can u tell me what's wrong in my commit , i couldn't understand it..

[susnux]

LGTM

Cypress CI will not work on forked repositories, so this is expected to be red

[welcome]

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