tray: Do not change scaling factor for image.

[shubham-padia]

Fixes #1364.

Changing the scaling factor of the unread image was broken on linux when the users were using fractional scaling. The icon looks all jumbled up. We default to scaleFactor 1 now, since an un-scaled icon is better than a jumbled icon.

Fixes:

Screenshots and screen captures:

Platforms this PR was tested on:

• Windows
• macOS
• Linux (specify distro)

I have not tested this on linux, which is the only platform this problem was occurring on. Supersedes #1365

Self-review checklist

• Self-reviewed the changes for clarity and maintainability
  (variable names, code reuse, readability, etc.).

Communicate decisions, questions, and potential concerns.

• Explains differences from previous plans (e.g., issue description).
• Highlights technical choices and bugs encountered.
• Calls out remaining decisions and concerns.
• Automated tests verify logic where appropriate.

Individual commits are ready for review (see commit discipline).

• Each commit is a coherent idea.
• Commit message(s) explain reasoning and motivation for changes.

Completed manual review and testing of the following:

• Visual appearance of the changes.
• Responsiveness and internationalization.
• Strings and tooltips.
• End-to-end functionality of buttons, interactions and flows.
• Corner cases, error conditions, and easily imagined bugs.

[mkaminsky]

I have not tested this on linux, which is the only platform this problem was occurring on. Supersedes #1365

Just tested this patch on my Linux laptop and it seems to work.
(KDE Plasma, Wayland, HiDPI/4K display, scaled to 200%)

Thanks for the updated fix!