fix(sharing): gate link password enforcement on always ask for password

[kristian-zendato]

• Resolves: [Bug]: "Enforce password protection" can be enabled without "Always ask for a password" #49819

Summary

• Gate password enforcement on "Always ask for a password".
• When "Always ask for a password" is off, "Enforce password protection" no longer applies in the backend, capabilities or share UI
• Admin sharing form still stores "Enforce password protection" separately, but only shows it when "Always ask for a password" is enabled

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)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI