[landscape] obfuscate registration_key in client.conf

[realstuffie]

landscape-client writes registration_key rather than registration_password, so the existing substitution no longer matched and the credential was collected in clear text. The replacement also dropped the separator, producing malformed output when it did match.

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Please place an 'X' inside each '[]' to confirm you adhere to our Contributor Guidelines

• [ X] Is the commit message split over multiple lines and hard-wrapped at 72 characters?
• [ X] Is the subject and message clear and concise?
• [ X] Does the subject start with [plugin_name] if submitting a plugin patch or a [section_name] if part of the core sosreport code?
• [ X] Does the commit contain a Signed-off-by: First Lastname email@example.com?
• [ X] Are any related Issues or existing PRs properly referenced via a Closes (Issue) or Resolved (PR) line?
• [X ] Are all passwords or private data gathered by this PR obfuscated?

[packit-as-a-service]

Congratulations! One of the builds has completed. 🍾

You can install the built RPMs by following these steps:

• sudo dnf install -y 'dnf*-command(copr)'
• dnf copr enable packit/sosreport-sos-4467
• And now you can install the packages.

Please note that the RPMs should be used only in a testing environment.