fix(sharing): Set correct password context for share password validation

[susnux]

• Was missing in feat(Security): Allow defining a password context for password validation and generation #47403

Summary

When validating the share password we need to set the context to sharing as otherwise it has the account context by default.

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)