Update the have_rsa_key to true property when a ssh key is created

[romainfrancois]

Intent

Follow up to #11182, adresses #8255

Approach

In #11182 we updated the "rsa_key_path" property, but we also need to update the "have_rsa_key", otherwise it's only set in UserPrefsComputedLayer::readPrefs().

This PR sets it to true

Automated Tests

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QA Notes

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Checklist

• If this PR adds a new feature, or fixes a bug in a previously released version, it includes an entry in NEWS.md
• If this PR adds or changes UI, the updated UI meets accessibility standards
• A reviewer is assigned to this PR (if unsure who to assign, check Area Owners list)
• This PR passes all local unit tests

[jgutman]

Good call, I didn't think of this, I was testing when starting with a key and switching key types/paths, but I didn't think to start with no keys. Thanks!!