[PM-3741] [PM-3750] Improvements to local storage handling

[mpbw2]

Type of change

• Bug fix
• New feature development
• Tech debt (refactoring, code cleanup, dependency upgrades, etc)
• Build/deploy pipeline (DevOps)
• Other

Objective

Improvements to the way we handle file attachment intents and storage restrictions

Code changes

• FileService.cs / Constants.cs / filepaths.xml: Convert to using specific path for temporary camera images using purpose-driven path restrictions
• MainActivity.cs: For non-camera attachments do not allow URIs pointing to our app's private storage. For camera attachments use the new temp path defined above. In both cases a resulting filename is required to continue with the attachment process as another layer of security.

Before you submit

• Please check for formatting errors (dotnet format --verify-no-changes) (required)
• Please add unit tests where it makes sense to do so (encouraged but not required)
• If this change requires a documentation update - notify the documentation team
• If this change has particular deployment requirements - notify the DevOps team

[bitwarden-bot]

Checkmarx One – Scan Summary & Details – fb6524f2-7131-41ce-accd-e91d6bddc417

No New Or Fixed Issues Found